Ask HN: What is the most impactful thing you've built?

During a centralisation of public school local servers to a data centre, I created a consolidated library enquiry system. It served over 2,000 libraries, had 330 million titles, and had about a million users. It was efficient enough to run off my laptop, if need be.

AFAIK it was one of the top five biggest library systems in the world at the time.

I was asked to add some features that would have been too difficult in the old distributed system. Things like reading competitions, recommended reading lists by age, etc…

I watched the effect of these changes — which took me mere days of effort to implement — and the combined result was that students read about a million additional books they would not have otherwise.

I’ve had a far greater effect on the literacy of our state than any educator by orders of magnitude and hardly anyone in the department of education even knows my name!

This was the project that made realise how huge the effort-to-effect ratio that can be when computers are involved…

> This was the project that made realise how huge the effort-to-effect ratio that can be when computers are involved

I love Steve Jobs' metaphor: computers as a bicycle of the mind [0]. Unfortunately, a lot of effort is concentrated on problems that scale to billions of people. There's a lack of attention to problems that would have a big effect for a relatively small number of people. It's a shame, because they're a blast to work on.

[0] https://www.youtube.com/watch?v=L40B08nWoMk

They really are. I think the most rewarding software I ever wrote was my first paid gig, where I automated lap swim scheduling for my local swim club. Took me maybe an hour, got paid more money than I'd make in two days as a lifeguard, and they were thanking ME for it. Turned out I had saved a volunteer upwards of an hour every week. With a shitty little JavaScript program.

The first time I heard that metaphor, I thought that he meant it in the way that bicycles are really fun to ride. I agree with both interpretations.

I have a bunch of small scale ideas that I want to implement. Not necessarily for profit. Any ideas on how to execute?

> had a far greater effect on the literacy of our state than any educator by orders of magnitude

Nice work, but check your ego mate. Seems your growth hacking would have had zero result if those kids couldn't read to start with, so you could share some credit ;-)

Maybe it wasn't meant that way. If they hadn't had been there then somone else would have been. You can be on the crest of a wave and not be responsible for its power.

By that logic, the people who farm the trees that make the books have more impact than anyone before them, unless you want to consider the people that make the tools, or feed the farmers, etc etc.

Cool story! what languages, frameworks, etc did you use? Or are you about to tell me COBOL? :P

The legacy back-end system being migrated was Clipper + dBase III on DOS, which is reminiscent of COBOL.

The part I added was built with ASP.NET 2.0 on top of Microsoft SQL Server 2005, and was eventually upgraded to 4.0 and 2008 respectively.

The only magic sauce was the use of SQLCLR to embed a few small snippets of C# code into the SQL Server database engine. This allowed the full-text indexing to be specialised for the high level data partitioning. Without this, searches would have taken up to ten seconds. With this custom search the p90 response time was about 15 milliseconds! I believe PostgreSQL is the only other popular database engine out there that allows this level of fine-tuned custom indexing.

p90 for a full-text search on 330 million documents was 15ms?

I know you can tune the hell out of search performance, but that seems a bit too insane for what looks like a relatively unspecialized setup (Standard DB).

Not likely the full book, just title, author and a few other low cardinality fields I'm sure. Also not likely 330 million unique volumes, but total books. This is within reach of a single database with proper indexing.

Can you elaborate a little bit more about how you partitioned it?

I simply added the "library id" as a prefix to almost every table's primary key. Every lookup specified it with an equality filter, so essentially it was thousands of standalone libraries in a single schema.

One hiccup was that when the query cardinality estimator got confused, it would occasionally ignore the partition prefix and do a full scan somewhere, bloating the results by a factor of 2000x! This would cause dramatic slowdowns randomly, and then the DB engine would often cache the inefficient query plan, making things slow until it got rebooted.

This is a very deep rabbit hole to go down. For example, many large cloud vendors have an Iron Rule that relational databases must never be used, because they're concerned precisely about this issue occurring, except at a vastly greater scale.

I could have used actual database partitioning, but I discovered it had undesirable side-effects for some cross-library queries. However, for typical queries this would have "enforced" the use of the partitioning key, side-stepping the problem the cloud vendors have.

Modern versions of SQL Server have all sorts of features to correct or avoid inefficient query plans. E.g.: Query Store can track the "good" and "bad" version of each plan for a query and then after sufficient samples start enforcing the good one. That would have been useful back in 2007 but wasn't available, so I spent about a month doing the same thing but by hand.

Impacting others? I started a Facebook group about a live stream for a falcon nest in Melbourne's CBD. It's had international news coverage and has been involved in a bunch of curriculums for schools around the world.

Personally? I built a heavy duty portable hard drive shredder than can shred a drive down to 1mm pieces in 60 seconds. Overall I sunk about $300k into the business and probably made back maybe $100k. I think we're 10 years ahead of the market, at least in Australia. But, it had huge impact on how I think about business, the customer, and how to pair the two instead of building awesome solutions no one needs (yet)

At work: the CDN for Megaupload. I was also the guy who had to shut it down when the FBI seized it.

Personal non-code project: The first adult LEGO fan conference in 2000. While I got out of that business years ago it has been replicated by dozens of other annual cons around the world. Back then the LEGO group didn't really understand and was very weary of adult fans. Now there's a whole reality tv show about them with LEGO designers as the judges, and LEGO actively supports cons and clubs.

Open source project: A project I released anonymously ~2010. Several github repos (unrelated to me) keep this project alive (the main one has ~600 stars and ~200 forks) and it's apparently used in several commercial products too.

Website: ip4.me/ip6.me serves 3-5M queries per day. I want to find a good non-profit to take this over to keep it ad and javascript free forever.

Thank you for the Lego thing.

My mom got into adult lego when she took apart my child hood lego and reassembled them to resell.

Now we mail each other sets that the other is done with, and it gives us a great opportunity to connect. We're both anxious people and there's something relaxing about just assembling something where everything has a place.

When she found out there's a lego con in my town, she made plans to come visit me so we can go together and I can show her around the city I just moved to.

That’s a wonderful story!

My 3 and 6 year old love lego kits. Historically I found myself sitting with them and helping when they got stuck or directing them when I saw they made a mistake. More recently I decided to pick up my own kit and build along side them. I’m currently working on the Saturn V rocket. It’s been a lot more fun for me and a way to bond with my kids.

>Website: ip4.me/ip6.me

>At work: the CDN for Megaupload. I was also the guy who had to shut it down when the FBI seized it.

>adult LEGO fan conference

Wow, what a small world. That's what I love about HN. The people that make things you use are on it :)

I wish I had something nearly as impressive. I just have open source stuff that people use. Nothing recognizable though.

Please tell me you're legally allowed to talk more about Megaupload and the work you did - sounds like an absolutely amazing blog post, would love to hear as much as you're able to discuss.

Also, I have a project in production at work where a device needs to grab its public IP address. My code has a list of sites that provide that info and I have ip4.me as a fallback in that list, so thank you for building it!

Legoland in my city still requires adults to be accompanied by children to enter. Kind of bizarre.

That doesn’t surprise me. It’s a very child focused park and I’m guessing they want to control the experience and environment as best they can. A bunch of high schoolers running around might change the dynamic.

> I want to find a good non-profit to take this over to keep it ad and javascript free forever.

Maybe worth reaching out to Mozilla. That's the only actual non-profit I can think of who I think would have both the ability and the incentive to keep it online.

> I think would have both the ability and the incentive to keep it online.

Ability? 5M/day for "what's my ip" is not much, and I'd wager most of us on this site would be able to keep it up and alive just fine. As for incentive... in addition to the Mozilla Foundation, orgs like Calyx, NLNet, Quad9 come to mind.

You are correct it uses very little resources, especially since most queries are http instead of https. Since there are no user accounts and it doesn't track anyone it doesn't even have a backend database to connect to. Just a couple dirt simple programs written in C with some very easy to remember domain names.

I'm not getting any younger so it's really about survivability. Transferring to another individual HN'er probably wouldn't solve that.

A non-technical nonprofit will fuck up regardless of the load. Beyond "keeping it online", it can be something as simple as "knowing how to configure the dns for it".

Impactful?

Designed and deployed credit card readers used in gas pumps back in 1979. (Sold to Gasboy)

Wrote a fine tuner to allow communication between satellites (precursor to TDRSS days). Still used to this day.

Failover of IP in ATM switches (VVRP, PXE, secondary DHCP, secondary DNS, secondary LDAP, secondary NFS). While not invented here, it is still used today as this is a Common setup to this day.

Printer drivers for big, big high-speed Xerox printers on BSD. Still used to this day by big, big high-speed printers.

Also, early IDS products (pre-Snort) at line-speed. Sold to Netscreen.

Easy zero-setup of DSL modem before some BellCore decided to complicate things (thus exploding their field deployment budgets; Southwestern Bell/Qwest enjoyed our profitable zero-setup). Sold to Siemens.

1Gps IDS/IPS before selling it to 3Com/Hewlett-Packard Packard.

Now, I'm dabbling in a few startups (JavaScript HIDS, Silent Connections, replacing the systemd-temp).

Impact? It is more about personal pride but its impacts are still being felt today.

How did you find all these product market fits?

Have you made more than a typical SWE?

It was actually a wandering hyperactive/ADHD mind that often said "why isn't there one" and follows through doggedly to the very end.

It is one of those traits where a mind clicks and said "this is it and how" and surprisingly gets into the most illusive hyperfocus/high-energy mode (without using any drug).

Slow-path network processing (arguably me) was commercially made in Ascom Timeplex in 1982 and someone else leaked it to Cisco (or ripping AT's patent off). I got that from observing how different river bends (re)connect year-after-year while doing trout fishing trips.

Money-wise, I am disabled, got abled, disabled again in different way, re-enabled, now just coasting with my own ideas: JavaScript Host-Based Intrusion Detection/Protection System, being one of them. And an portable AirPod detector (for home/auto/travel) is another idea. And DNSSEC for within private enterprise is almost done.

Money is not my thing but it does help greatly in the pursuit of my ideals (so many hardwares, so many test equips).

Wow. You were the original querySelector. It's funny how you forget that somebody actually sat down and wrote these things into existence at some point. Thanks!

Even more impressive to me is writing things into existence without the benefit of being able to dig in to the underlying browser tech, and only being able to use the public (at the time) DOM APIs like getElementById, etc.

He's understating, perhaps on purpose.

Datasette, Django, and Lanyrd.

Ten years ago I was reading [0] and I remember your name was mentioned somewhere. Here is a quote:

> Locating elements by their class name is a widespread technique popularized by Simon Willison (http://simon.incutio.com) in 2003 and originally written by Andrew Hayward (http://www.mooncalf.me.uk)

[0] Page 91 from "Pro JavaScript Techniques" by John Resig.

Hey Simon, thanks for creating Django with Adrian. I was deeply interested in programming from a young age but learning Django in my teens sparked a passion for web development that has yet to feign so many years later! Appreciate all your contributions to this space.

Wow, 10 years before document.querySelectorAll()!

A pipeline approval tool (internal at Amazon) that counts metrics.

I was a fairly fresh college-hire SDE1 at Amazon. And I was annoyed, because I'm lazy. Every time I was oncall, I had to manage the deployment pipeline for my teams software- the UI for the tool used by Pickers inside Amazon Warehouses. On Monday, deploy the latest changes to the China stack (small). On Tuesday, check if anything bad happened, and then deploy to the Japan stack (small-ish). On Wednesday, Europe (big). Thursday, North America (biggest). Repeat each week.

And I thought "why am I doing this? There are APIs for all of this stuff!". So I made an automated workflow that hooked into the pipeline system. You gave a metric to look for, a count of how many times the thing should have happened, and an alarm to monitor. If everything looks good, it approves. I hooked it up for my pipeline, and then it usually finished the entire weekly push before Tuesday afternoon. I made it in about 2 weekends on my own time.

And I left it open for anyone in the company to configure for their own pipelines. A few weeks later I was checking if it was still operating normally and realized there were something like 50 teams using it. Then 100. Then a lot more.

The last I heard, it's considered a best practice for all teams within the company to use it on their pipelines. Before I left in 2021, it was running something like 10,000 approval workflows per day.

I named it after the BBQ/grilling meat thermometer in my kitchen drawer- "RediFork". Given the overlap of "people who read HN" and "devs who worked at Amazon", I probably saved someone reading this an aggregate hour or two of work.

I had always wondered why it was called "RediFork"... thought it might have been using Redis or something.

Thank you for creating it!

First job out of college, I was at a consulting firm doing software development for DHS (Homeland Security). I got a lot of flack from my friends and family for "working for the devil", but the work was actually objectively good for society - basically there was a big data problem where when an immigrant trying to illegally cross into the US was apprehended, and if they were sick, their custody would be transferred from US Customs and Border Protection (CBP) to Health and Human Services (HHS) so they could receive medical attention. There was zero data transparency between these two orgs, so when that transfer happened it usually caused families to be separated (Sick dad, healthy mom and child, sick dad gets brought in for care and never finds his family again). Since HHS and CBP don't have data communication and everything is siloed, the handoff was really poor and they often wouldn't find each other for months afterwards.

There was a lot of talk about this in the news, and although the software I was working on didn't entirely fix the problem, it allowed the agencies to communicate better. Their data wasn't siloed, and families got separated for only a few days rather than (sometimes) permanently.

I really miss that job. The pay was atrocious and zero WLB, but everyone agreed it was an important problem to solve, and I think the tool we had built really was helping.

Sadly true and relatable. Thanks for fighting that good fight.

A temporary low resource form for people in Puerto Rico to send an SMS message out to family outside of PR after Hurricane Maria.

During Hurricane Maria most of Puerto Rico was offline. Slowly but surely, some people started having access to some online services. To this day, I don't know how, but I saw frequent posts in social media (Facebook and others) of people saying they could access spotty internet but SMS and making calls wasn't working, and asking people to let their family outside of Puerto Rico know that they were okay.

So I setup a site on glitch.com with real simple 2 field form. One for a phone number and another for a message to send. It was dead simple, no framework, no CSS, just little bits of vanilla HTML and JS, and a bit of backend code connected to Twilio. Some text on the top with instructions too. I was making it intentionally small so that a spotty connection wouldn't have a problem using it.

Any time I saw someone posting in social media asking for someone to reach out to their family, I posted a link. I also shared it in a slack where many from the PR diaspora where trying to contribute ways to help. Before I knew thousands of people were using it. I did some continuous monitoring to make sure nobody was using it for abuse, and making sure it was being used as intended. It would have been EXTREMELY easy for someone to abuse it if they wanted to.

No one abused it. Thousands used it as it was intended. Left it up for weeks, and I kept monitoring it to make sure it wasn't being abused. I eventually saw it had stopped being used entirely for two weeks and spun it down.

I saw some people posting about it afterwards being thankful they were able to receive messages from their family, and I'm happy I rushed through to write very sloppy high impact code.

Awesome story, well done putting it out there, glad nobody abused it and thanks for sharing!

Monodevelop, I think: https://www.monodevelop.com

It wasn't a planned thing. I had recently got injured playing football, so I was stuck at home, not being able to walk or drive. I started checking the #mono IRC channel (it was 2003 and internet was something you did over a 48k modem, when your home phone line was not needed). Some guys, lead by Miguel de Icaza, the founder of Gnome, were implementing a compiler of C# and a bytecode interpreter of .NET IL, and I was very curious about it. I kept downloading, compiling and trying things out.

Then one day Miguel wrote in the channel that it would be nice to have some graphical editor and that somebody could perhaps port SharpDevelop over to Linux, by replacing Windows.Forms by calls to GTK. I said that I'd give it a shot and... well, 10 days later we had a working editor and half a dozen of contributors.

https://tirania.org/blog/archive/2008/Mar-14.html

I love MonoDevelop, I used it to write C# for Linux before the .NET core days

In late 2013 I came up with the first memory hard Proof-of-Work puzzle, Cuckoo Cycle [1], based on finding fixed-length cycles in random graphs. Recently, custom chips were developed to solve it more efficiently than GPUs can.

That probably had more impact than the Binary Lambda Calculus language I designed [2] or the logical rules of Go I co-formulated [3].

Computing the number of Go positions [4] or approximating the number of Chess positions [5] had little impact beyond satisfying my intellectual curiosity.

[1] https://github.com/tromp/cuckoo

[2] https://tromp.github.io/cl/cl.html

[3] https://tromp.github.io/go.html

[4] https://tromp.github.io/go/legal.html

[5] https://github.com/tromp/ChessPositionRanking#readme

> the first memory hard Proof-of-Work puzzle

Scrypt is from 2009, per Wikipedia. That's memory hard, and using hashes with some zeroed out bits is a thing done for a long time (Bitcoin 2009; some old meaning of "cryptographic pepper" (fallen out of use) that iirc dates back to the 90s). Am I misunderstanding what you built?

Scrypt [1] is a password based key derivation function (PBKDF), which can be used as a hash function that takes a configurable amount of memory to compute.

The reason it makes a very poor PoW (as choice of hash function in the Hashcash Proof-of-Work) is that the PoW verifier needs as much memory as the PoW prover, whereas a good PoW should be instantly verifiable.

This is why blockchains using scrypt as hash function severely limit the amount of memory used (usually to 128KB). So that verification, while slow, is not horribly slow.

Cuckoo Cycle also requires a configurable amount of memory to solve (subject to certain tradeoffs), but crucially, can be instantly verified with no memory use at all. And thus makes for a good PoW.

In the form of the Cuckatoo32 variant that most mining takes place with, it requires 0.5 GB of SRAM and 0.5 GB of DRAM to solve most efficiently.

[1] https://en.wikipedia.org/wiki/Scrypt

> the PoW verifier needs as much memory as the PoW prover, whereas a good PoW should be instantly verifiable

Ooh, yes I see, that is a big difference. Cool work!

SCrypt was thought to be memory hard. It was not, and making asics for it ended up being pretty trivial.

Scrypt is memory hard. The reason ASICs were easy to make was the small memory requirement chosen to make PoW verification not too slow.

In 1995 I (and a few others) designed and built the first WiFi node [1]. At the time there was only one WiFi unit in the world, and it was the one on our bench. It now has about 20 billion descendants.

[1] https://sci-hub.se/https://doi.org/10.1109/40.566198

Pokemon GO.

It was such a surreal moment to finally leave the office after months of crunch time, walk out into the sunshine for lunch for the first time and see almost every person on the street playing the game.

Bits of it. I wrote the code to figure out where on the planet all the pokestops and gyms should go, for example[1]. But there were five other backend engineers by the time we launched, plus a bunch of front end people, artists, etc.

[1] To be extra-clear, all code in the game was touched by more than one person, every one of them better engineers than I am.

I was a contributor to a little pair of libraries called KHTML and KJS, a HTML renderer and JavaScript interpreter. Joined about a year into the project and while I didn't lay the foundations I helped improve the DOM and JS support a fair bit.

People I respected told me I was wasting my time because Internet Explorer was the de-facto standard and the idea of a new browser engine becoming prominent was fantasy.

Then Apple decided they wanted do a browser and looked around at what open source engines were available they could use as a starting point. Thus was born WebKit [1].

I consistently ignore anyone who tells me I shouldn't try something because it's "too hard" or "nobody will use it". Most of the time they turn out to be right. But not always.

[1] https://marc.info/?l=kfm-devel&m=104197104218786&w=2

Edit: Here's an interesting presentation by Lars Knoll and George Staikos on the history of the project: https://www.youtube.com/watch?v=Tldf1rT0Rn0

> I consistently ignore anyone who tells me I shouldn't try something because it's "too hard" or "nobody will use it".

Inspiring. Thanks for your contribution!

I guess my most impactful project was a microprocessor-based weather station for siting wind energy systems and fruit frost prediction in the early 1980s. Turned out that one of my stations, being used by a frost predictor, was across the street from a rural drainage ditch in which a young child was discovered face down in the water. The frost predictor faxed temperature profiles for the previous several hours to the hospital, where doctors determined the child could be revived. She was.

Wow! That's a pretty amazing story. Thank you for sharing.

Thank you! Took me by surprise when my client phoned and said my weather station was on the evening news.

Interesting that one my the developers on my projects was Dan Wood.

wait... they won't try to revive a child unless they can first prove that said child can be revived? Why not just... try to do it regardless and hope for the best?

Also, as a new parent, my immediate thought is of course "WHO wasn't watching the kid??"

Just a guess, but it might have something to do with whether the brain is able to be saved vs. just the body.

Let's Encrypt (along with the coauthors of https://abetterinternet.net/documents/letsencryptCCS2019.pdf and many other contributors). Now the world's largest public certificate authority!

A hotel concierge that’s helped 50 million guests during their stay. The goal is to create unforgettable experiences for a billion people!

Ivy sends you a text message introducing herself as a virtual concierge when you check in. She answers FAQs in 1 second using NLP and routes anything more complex to the front desk team for resolution in 2-3 minutes. All in one simple text thread, no apps or UI needed.

Guests often come to the front desk trying to tip Ivy, rave about her in reviews, ask her out on dates, and even drop off hand written thank you notes for her.

One woman texted Ivy in a panic asking about the nearest drug store to buy Benadryl because her son was having a severe allergic reaction. A guest service agent brought Benadryl to her door in 3 minutes at a large Las Vegas property. She called Ivy a life saver.

In terms of value per person probably improving the faceted search marginally on one of the biggest auction sites in the world.

In terms of the impact I care about, I try to give aspiring programmers my time and talk to them about how they can improve their hirability by building useful skills that you'd use day to day. I haven't had much success, but the little success I do have was helped in large part by an influential mentor. Those can be hard to come by, and time is expensive.

I was about to say I built this beautiful IVR for a taxi company 20 years ago. It was so good, solved so many of the annoyances I had observed with IVRs before… so perfect it was, that it remained untouched all these years… I was about to say that. But out of nostalgia I just called the number and it’s been replaced with some Byzantine piece of crap.

Despite being in the industry a long time, I think most of what I worked on had little to no impact.

In terms of impacting other people, probably the biggest thing was blog posts and sample code. It’s funny how sample code has less “cred” than “real” code, but if you’ve ever been trying to start a new project in a new language or framework you know how invaluable sample code can be.

In terms of impact in general, what I’m working on now has been the most impactful , because it’s improved my health. Im trying to innovate on the concept of a habit tracker. Since I started working on it, I’ve lost 10 pounds, quit drinking, went from about a gram of marijuana use a day to about a gram a month, quit addictive video games, went surfing much more consistently, and been able to put in many more hours of focused work than I ever have before despite working alone and only being accountable to myself.

Generally when Ive gotten feedback about the project, I’ve gotten told it’s too complex, people want simplicity, I should focus on B2B, and I shouldn’t write any code at all unless I’ve validated a problem. I try to communicate to people that I don’t want to sacrifice my own health progress to simplify things. But I am hoping long term I can figure out how to build a bridge between what’s effective for myself and what’s appealing and understandable to everyone else. Lots of work to be done! But I think improving my own life a lot more impact than most of the stuff my employers had me doing :)

>Despite being in the industry a long time, I think most of what I worked on had little to no impact.

This is kinda what drove me out of tech a few years back... I could point to tens of millions (at minimum) of people who had used my work. I could point to hundreds of millions in net revenue / cost savings for my employers and clients. But was it "impactful"? IE: was any major world problem solved, or were lives actually made better by my work? Even worse, the three coolest projects I worked on - seriously cool tech, highly scalable, etc - I'm not sure ever really saw the light of day because they were killed by changing business goals. Hard to feel motivated when you know you are doing good work but its all ephemeral.

Isn't that amazing? And yet there are so many of these jobs. They pay well too.

https://www.inaturalist.org/

While I deserve no credit for its current success, it's been used by millions to:

* catalogue millions of plants and animals around the world

* tagged image data has become critical for computer vision training models

* map species range and impact of various natural changes to biodiversity, with data cited in scientific journals

* new species have been discovered through the app

previous HN thread - https://news.ycombinator.com/item?id=22442479

My wife (and sometimes me) use it. It's awesome!

I created Tiny Flashlight for Android 12 years ago. It's been downloaded almost 500m times. Back then every hardware vendor implemented the camera API in their own way and it wasn't easy to start the camera led. I had to purchase many different devices from different carriers from all around the world just to find out a way to start the camera LED. It was very helpful when the vendor published the kernel source code with the camera drivers for the particular device model. I could send custom commands to the driver to start the LED, where it was not possible using the standard camera API.

How many Android phones does it take to turn on a lightbulb ...sorry.

I'm one of the founders of ODK[1]. It's an open-source offline data collection app that, according to WHO[2], helped eradicate wild polio from Africa. It's become the de-facto app that social impact orgs (e.g., Red Cross, Carter Center) globally use to collect data in the field. It's kinda wild to think about, to be honest.

[1] https://getodk.org

[2] https://www.africakicksoutwildpolio.com/the-top-five-tech-so...

We never met but I had evaluated ODK for the Sharedsolar project at Columbia U for data collection purposes. I used to work alongside mberg and ODk was an indispensable tool for nearly all the health initiatives and surveying. Truly impactful, congratulations!

I love ODK! I've worked with it for a community health volunteer program and contributed a bug fix, even. The impact of ODK goes beyond the software itself, since so many other survey platforms use it as their base. Kudos and thanks from everyone in global health.

I created https://infect.info which is a software used by doctors to determine the best antibiotic to subscribe to patients based on symptoms or bacteria properties.

The software helps save lives on a daily basis.

It uses recent data from lab tests to show which bacteria is resistant to which antibiotic.

I built the first "post-play" experience for Netflix. It made it so that Netflix would automatically start playing the next episode of the show you are watching after a 15 second count down. We built it in the Silverlight player on the web because it was the fastest way to A/B test new features at the time.

Before post-play, you had to open the episode menu and click on the next episode to play it. We didn't want to do autoplay for a long time because we were afraid people would fall asleep with Netflix playing and it would break the internet. So we included the now infamous "Are you still there?" popup a few minutes into episode 3 with no interaction with the player.

Now it is everywhere - YouTube, Hulu, HBO, etc. And people watch way more TV than they should.

I want to say I hate automatic playing of content after my content is complete but when I really think about it I love it when I want it to do that and hate it when I don't and i'm too lazy to tell my UI which is which.

I guess when something just works your users will assume the cases where it is working properly are just the way things are and the cases where it does something they don't like is your fault.

So well done!

I miss contemplating the content I watch. The attention economy has really perverse incentives. No thinking, only consuming.

As I was reading your comment I was thinking "whoa, that sounds like Damien or Robert" and sure enough :)

Hope you are doing well!

I prototyped this as a Java Robots in like 2011 so I could fall asleep to Futurama. I guessed Netflix would take steps to ban it, but later they embraced it.

Ah good old Silverlight. I once wrote a Drag and Drop library in SL. Good times. I miss XAML.

I work in video games and have worked from writing gameplay code all the way up to online infrastructure. It's only been "impactful" culturally, rather than some of the other posts. My top highlights are:

https://www.nytimes.com/2019/07/28/sports/fortnite-world-cup...

I was a programmer working on Fortnite, and I ended up working on the on-site fortnite events, doing everything from the custom cameras and broadcast specific UI, to hooking up the events in-game to the lights in the stadium. It was pretty cool!

https://youtube.com/watch?v=EWANLy9TjRc - I worked on this game (and the demo in this video) for a few years. I wrote much of the code for the asset pipeline for the destruction, lots of the gameplay code for how it interacted with the game and a good chunk of optimisation on the cloud physics side.

How I lost my first pension: I built an invoicing system for a friend's phone repair business that I licenced for a modest monthly fee. Over the next 10 years I gradually added more features as the business grew to 36 retail stores and built the product into a proper ERP system, rewriting it twice to keep up with new requirements. Eventually I sold the IP to them for cash and stock and became CTO at 27. It was a fun, but difficult time.

Unfortunately, the founder raised way too much money on unfavourable terms and hired the wrong people, which forced the company to expand at an unsustainable rate and drove all the good people away. The company overextended itself and entered business rescue soon thereafter. The company is now a former shell of itself, but my product handled millions of rands and over 500,000 repairs. What I lost in a pension, I gained in an MBA.

Wow, weird to think about.

Nothing. I haven’t built anything with a significant impact. I’ve made things that made a significant impact on businesses, but in the scheme of things, nothing exciting.

The thing I made which generated the most revenue was easily the most harmful, and likely the most impactful. Unfortunately. It was an ad exchange that did extremely well. The owners went from random guys with a gross idea to multimillionaires in a couple years. They both spend their days buying up startups.

I should have done better by now. I feel like I need to make up for building that exchange. I was young and had no idea what I was getting into until it was too late.

You’re not alone. I’ve been doing better in the last few years but when I was just starting out as a web developer set on building a successful SAAS, a lot of them were marketing/advertising related. One of them is a pop-up builder… Sorry!

It still brings in some revenue but I have been intentionally neglecting it for years now, as I personally hate those things with a vengeance. But still, I don’t pull the plug on it.

Yeah, just a few weeks ago I saw an ad for an institutional real-estate investing platform that buys single-family homes. Not every software should be built.

Wrote del.icio.us and invented tagging. Echoes of my original design are still around (notably account urls being web.site/userid)

I took couple years off coding to build a Kenyan infrastructure engineering firm - we're still going although I've started programming again. The biggest thing we've done is 6.7km of a mountain / lakeside ring road in Homa Bay on Lake Victoria (Kodula village section specifically, the work is visible on satellite). We're actually not completely done with it but watching the community growth from having the paved road reaching completion and improving the accessibility was absolutely incredible. Extremely frustrating sector to work in and difficult to pay yourself a salary even when it's not charity, but sometimes the rewards are awesome. I have a physics background so doing civil / electrical / mechanical stuff is tractable for me beyond programming, then we use the classic PM tooling to make things run ~relatively better than most people doing stuff out there. All Kenyan engineers other than me, lots of smart people who are highly motivated to meet and work with.

Moving atoms must be 6x10^23 more satisfying than slinging electrons. Kudos to making the leap to building infrastructure for the community.

May I ask what made you take the leap?

When the big earthquake in Nepal happened in 2015, I was working with a volunteer organization called Translators Without Borders to help with translation during relief efforts. Since I was in the USA I could not contribute back physically, so this was the next best thing.

My goal was to help volunteers that were in the field in Nepal communicate in English -> Nepali and back. Even though this was somewhat effective, there was still a communication gap because most people in Nepal in remote parts could not even read in Nepali.

I looked around for solutions but couldn't find any Nepali Text To Speech solutions. The builder brain in me fired up and I decided to build a Nepali Text To Speech engine using some of the groundwork that was laid by Madan Puraskar Pustakalaya (Big Library in Nepal) which they had abandoned halfway.

I spend all night hacking along to build a web app that let the volunteers paste translated text and have it spoken. The result was https://nepalispeech.com/ and the first iteration of this was built in just 13 ish hours.

I hope the people that got affected by the earthquake are in a better situation now.

I spent 11 years working as a contractor for the U.S. State Department. During this time I:

- In 1996 built and deployed a system to keep track of the removal of landmines in Bosnia. In 2015 I met someone who knew my work as a child in Sarajevo, producing the maps they’d give out to schoolchildren.

- I managed a project with over 30 team members to build a system to help former Soviet Union countries manage their import/export control policies.

- I helped create a system for generating some annual reports for Poland that was a requirememnt for them to join NATO.

Never worked for the federal government but my first “real” full time dev job was at a small state government agency and the work I did there had very visible positive effects for people interacting with the agency. Pay was really low though.

A long time ago I worked for one of the big medical journal publishing firms. (No, the other one.) I was one of the lead software developers, nominally in charge of the web application that served all of our licensed content to medical professionals and librarians all over the world. I was senior enough at that point that I attended regular planning meetings with the CEO and her team.

We were working on a new product, electronic access to textbooks. I'd built the entire system that takes the textbook XML we got from the content side, created indexes used by our search engine, and made it possible to efficiently display in the web application any text fragment from a full chapter down to a single sentence containing a search result.

The CEO called an emergency meeting: many of our library customers were government funded, and their funding required the library to receive a physical object in exchange for the licensing fee. They didn't want to have to store the physical textbooks and we didn't want the overhead of sending them textbooks. So the team starting talking about creating an entire new subdivision dedicated to the production, management, warehousing, and shipping of CD versions of the books, just so the customers could be given something physical.

I interjected: "If a CD is good enough, I can generate that using everything I've built already. I'm already converting the content to HTML for display in the app, so I can render the textbook out to a folder, one HTML page per chapter, with a table of contents and all of the images, and create an ISO image that the librarians can download using a link in the web application. Let them burn it themselves if they want a physical copy. They could also store the ISO locally so they still have that version if they let their license expire." That was a funding requirement as well.

So that's what we did. It took me a couple of days extra to implement that feature, and I saved the company a fortune compared to what they were considering doing.

I believe I got a $25 Starbucks card as a reward.

That's an annoying part about capitalism.

For example, the guy who invemted the process to create artificial diamondsnfor GE,got a nice plaque and $1.

Probably political stuff, for better or worse:

* Made it easier to create a limited liability company in Italy: https://blog.therealitaly.com/2015/04/16/fixing-italy-a-litt...

* Pro-housing organization here in Bend, Oregon: https://bendyimby.com/

Software wise, I really enjoyed my time working on these devices: https://www.icare-world.com/us/

Hi! Just signed up for Bend YIMBY :) Thanks for sharing that.

Fixing bureaucracy is a gift that keeps on giving. Well done!

Reading your comment I thought this was going to be a darkweb site for cheap pharma stuff from Canada/Mexico to the U.S., did not expect straight up drugs.

oh wow. you were adamflowers? did you just get out of prison? glad you have no regrets, I can't imagine how much serving that much time must suck.

My most impactful project was definitely NoCoin [0], the first web miner blocker. Back when Monero miners started appearing and sneakily mining on pages, like The Pirate Bay for example, I decided to throw together a browser extension that would simply block requests to the resources that hosted these mining scripts. The project was in no way a technical achievement, it was simply intercepting requests and blocking them based on a list. I could have very well added the resources to some other project like uBlock origin. But it got traction, ended up in the press (WIRED, Motherboard, Gizmodo) and ultimately started being integrated within browsers (Opera was first) and most of the popular ad blockers. The project lost its relevance as everyone else was doing it better and maintaining the list of blocked resources was too time consuming for me. Nevertheless, the goal was achieved, which was to "get rid" of crypto mining on the web. The mission got carried by bigger actors, which brings me more satisfaction than the popularity of the project.

Another impactful project of mine was also a browser extension. Internal tool that started as a lunch time project to make my team's life easier. Can't go in detail on that one, but basically they liked it and start suggesting improvements. So did a department that was working with us. And bit by bit, it became a really useful tool that became standard in these departments. Last I heard, the tool is now deployed company-wide. Crazy to think it started just from some lunch time hacking :-)

[0] https://github.com/keraf/NoCoin

I designed and implemented the whole graphic system for the World Cup '98 (working 100h weeks for months). Billions of people have watched in real-time the result of my work and I earned absolutely nothing from it :) (there's a fun story to write about this, the tremendous amount of work, setting up the WAN connecting the SGI machines together, building the remote control hardware, etc).

As a football fan and obsesive, France 98 has a special place in my heart because it was my first world cup as a child (I am from 1990, I wasn't fully aware in USA 94), so please please please write more about this.

World Cup '98 was the bomb! Your work is part of an amazing history.

Quite insane. If you ever write about it, I'll surely be reading.

About 14 years ago - before I'd taken as much as an intro to CS class - I wrote some software that helped a bar keep track of who'd drank what. They were the type of bar where, if you drank every beer they had available, you'd get a free mug. Prior to it being computerized, the staff used index cards in shoeboxes. Lots of the wait staff's time was lost fumbling through those boxes, unsticking them from each other (gross!), etc.

I've since gotten a degree and written software for a handful of companies.

When I think of how many people are actually _using_ my software, though? Fourteen years later, the mug club software is still live in a production environment, used every day by wait staff who turns over every few months. No doubt hundreds - potentially thousands (it got deployed at a few different bars) - of people have interacted directly with it. That code embarrasses me nowadays, but as far as impact goes: that's probably it.

It is amazing how much you can do with code when you only have minimal knowledge and the desire to make something work, before having ideas of "how it should be done" or "how to do it right"

After school I did an IT support role for a further education college.

They used to spend most of the summer formatting the machines, reinstalling Windows, office, anti-virus etc, doing them manually a classroom at a time.

We replaced it with a system of hidden partitions and a disk image, then the ability to trigger a refresh remotely if pre-requisites were met.

This is common practice nowadays, but it was quite innovative at the time, and we had to write a lot of the code ourselves for remote admin and to make the disk refresh reliably.

We could then click a button and refresh ~500 machines in the space of an hour as opposed to 6 weeks of manual labour.

I've worked on more prestigious stuff, but that was the most satisfying and the most obvious avoidance of manual efforts.

Probably bsdiff; a few hundred lines of code hacked together over a weekend has saved people over a hundred thousand years of waiting for software updates to download.

Next up is probably scrypt; it would rank higher if cryptocurrencies used it, but instead they use nerfedscrypt which defeats the entire point of scrypt.

Third is probably FreeBSD/EC2. Of course I didn't do all the work for that, but I can certainly claim the status of technical project manager.

My day job, Tarsnap, comes in fourth.

You forgot my favorite cperciva project: spipe

I didn't forget it, and it's one of my favorites too -- but I don't know if it qualifies as the most impactful. People who use it love it, but it's not very widely used compared to, say, bsdiff.

I created some of the early Android and ios football result apps back in 2011. I used to work as a regular dev and became relatively rich somewhere in 2013. It gave me room to start other businesses and become financially independent.

The Windows Terminal. It was a long journey to get the console code fairly modernized and maintainable. Another long journey to build a whole new application that could be compatible with the old. And years now of iterating of that original prototype, out in the open.

It's not a perfect application, by any means. But the bar was _so_ low, that I can't help but think of how much we've helped users just over the last few years.

I guess, my internship project at Apple: I added approximate string search to Spotlight.

So even if you made a typo writing something, you’d still get correct search results.

Considering Spotlight is used by millions, I guess that’s super impactful?

It's hard for me to say. I've written a few random open source projects for Wordpress and Webpack that consistently get a few hundred daily downloads even 7 years later, but it's all behind the scenes stuff that doesn't really get talked about even by the people that use my projects.

I've also created a question-based card game for social connection that I produced and sold 200 units of. Far less scale, but people tell me weekly about the impact that it had on their lives and the connections that they formed through it. It's really shaped the values of the social community I belong to, so in a ripple effect kind of way, I think it's had a pretty huge impact.

And I've also worked on some widely used web apps for NASA and OpenStreetMap, written a lot of code and shipped some big features but only as a productive IC.

Contemporary Art Library, a massive non-profit archive of documentation that will organize, preserve and make accessible the art history of our time[1]. How long that will take depends on the extent to which we can learn how to fundraise, but we already have more than 400,000 pieces of media (images, documents and video) documenting exhibitions, performances and other public artist activity from all over the world. If anyone knows any internet-friendly funders that might want to help accelerate our efforts, let me know! [2]

I created the organization, did the design and helped a colleague building the software. We've had more than 4 million visits from 300k+ users (distributed throughout the world, roughly in proportion to the interest in contemporary art in those countries) and continue to grow most months.

[1] https://contemporaryartlibrary.org [2] forrest -at- contemporaryartlibrary.org

I built the national covid health information system (NCHIS) for my country that helped to mitigate the pandemic. It streamlined the sample collection to issuing reports and aggregated data nationwide and generated reports for government to make decisions on lockdowns and track the pandemic progress.

Well this was not completely built by me but I got help from 20 odd university students but I overlooked the project and did lot of coding myself. Even though it’s not used now since the pandemic has settled I’m happy what I have done.

> I overlooked the project

May I suggest "oversaw"?

https://en.wiktionary.org/wiki/oversee

https://en.wiktionary.org/wiki/overlook

Even though both words have older meanings that are somewhat opposite of their current meanings, "oversee" is normally used today to mean "supervise" or "superintend" (in fact, I suspect "oversee" could be a calque of "supervise"), while "overlook" is normally used to mean "ignore" or "fail to perceive".

When we were all WFH'ing during Covid, I couldn't stand listening to presenters saying "Next slide please" over and over. We use Google Meet at work and it doesn't provide any way to give others control of your desktop or slides. So I built a Chrome extension that allows multiple users to control a Google Slides presentation from within Google Meet. It's only got about 2K installations, but people have simulated almost 250K slide clicks with it in the past 3 years. So this is probably my most impactful contribution, especially on my own mental health having to never hear "Next side again".

Homepage: https://fonner.gitlab.io/shared-slides-clicker/

I wrote a blog about some of the trickier parts of building it here: https://jedfonner.com/2020/11/06/shared-slides-clicker/

I was a warehouseman in the Marine Corps in the late 90s. Our warehouse was absolute garbage. we couldn't fill something like 30% of our orders because we couldn't find the items or the inventory was off. We were also still running on nightly batches from some IBM AS400 system. I wrote a receiving program to print labels and properly assign stock locations to incoming inventory. Coupled with better control procedures we turned the ~$4MM operation around and ran at over 99% efficiency. Earned myself two NAMs for that work. It was 100% VB with a custom flat-file database.

Then I stopped working on software for ~15 years because I burned out

In an MA program in biblical studies, I realized that the best way to understand what words mean in context is to see how they're used in similar contexts. To do that, you've got to be able to find similar contexts. I didn't like the solutions available from the major software vendors, but it turns out there's a whole bunch of tagged data that's openly licensed. So I built a webapp that has all the search functionality that I need and I put it online (https://parabible.com).

Apart from word of mouth and the occasional post like this, I don't advertise it, but it's getting about 100 users a day. Many of my users come from the majority world and couldn't afford the software from the major vendors, which is very gratifying.

When I was in college I wrote a Windows app to do the side-by-side translations of the bible just like you have on your site.

It was commissioned by a multilingual church.

Funny thing is, I'm a atheist raised by Catholics. I'm not sure if I would take the job today. I feel it would be unscrupulous for me to facilitate religious studies.

I mean, parabible is really aimed at research. In that sense, hopefully there's something useful about it as a tool for study, irrespective of personal convictions. That said, I'm a Christian and I'm studying the Bible because I believe that's how we know God, and I would be the first to say that there is something different about that kind of research.

I like the layout of this. Do you plan on adding any other versions of the text? BibleHub also shows multiple versions of the text, but has a wide variety of translations to choose from. Though their layout isn't quite this elegant

Thanks, I have put a non-trivial amount of thought into making the interface friendly. I appreciate the compliment :)

I've got a staging environment at dev.parabible.com with other versions (it's a bit rougher and can break, but it supports searching in Greek along with a bunch of other translations). I've also added Apostolic Fathers there (which, I believe, is the first place that Ap. Fathers have been available in English and original language in parallel for free anywhere).

I'd love to get versions like the ESV, NIV, NASB... but they're all copyrighted and when I've spoken to publishers about licensing they want me to pay (and I'm a grad student with no income). There are some other free translations I could add (like the KJV, etc.), but I'm aiming at a scholarly audience, who I think don't care about most of the translations that you'll find for free (the KJV is one exception there, tbh).

This is really cool. It's quite sad that the other versions are under copyright. The KJV is probably the one that people would look for the most as a baseline, I think.

My holy grail (no pun intended) is the pre-Challoner version of the Douay-Rheims Bible. There is a PDF scan of it up on archive.org, and a seller produced books of the text but with their own Old-English-to-English translation, but I haven't found any text-only versions of the original online

I am not sure I want it to be this, but back when I worked on software for airports, there was a concept of a Target Startup Approval Time (TSAT). This is the moment an aircraft is expected to power up in preparation to roll back and taxi to the runway before taking off. I worked with some clever statisticians who were focused on optimizing this exact moment. That calculation has hopefully contributed to reducing more pollution than anything else I could conceivably do in my lifetime.

That's incredibly boring though, and I work in sport now. The most _emotionally_ impactful achievement is the first soccer player signed based on my statistical models. He helped win his club their first title in a decade, got his first international callup, and won his country their continental cup (he also made his club a lot of profit when they sold him and my sell-on percentage never materialised).

Over the last 4 years I built a label design and print app using Electron/React. It has 5000+ desktop users and will reach 7 figures in revenue in the next year. I recently launched a new thermal label printer brand named mydpi. Right now I'm selling a 300 DPI direct-thermal version to compete with DYMO and low-end Zebra. In a month I'll launch a thermal-transfer version with bundled ribbon/labels. I never thought I'd play in the "label printer" niche, because honestly, I hate printing labels... but my app makes it possible to easily achieve impressive results. I'm also working on a cloud-based renderer that will make user's designs available as an API that accepts variables for inside the label and returns a rasterized image or the specific-printer-language to print the result.

My life's work...

https://label.live and https://mydpi.com

I just watched the entire label live video demonstrating the features. Looks super solid and easy to understand. Great UX all around. Nice work.

Definitely All About Berlin. A few years ago, I started documenting how to deal with German bureaucracy as a foreigner. The website grew and grew until it became a well-known resource for immigrants. It has become my full-time job at some point in 2020.

It's been a little over 5 years since I started, and I'm still super stoked about my work. I still enjoy doing the research, rewriting guides a dozen times, and answering reader mail. People seem really grateful for it, and it means a lot to me.

I use your site often. Thank you for creating it, it's a great resource!

That's awesome! Wish I had heard about it when I moved there, definitely going to hunt through the site to see if you have a guide to getting some of my pension payments refunded now that I've moved

I've developed an application that presents information about a patient's circulatory system to anaesthetists during surgery to give them clearer information about the patients heart and vasculature so that they can make finer grained, individualised treatment decisions. There's currently only a small group of users, as we haven't been able to afford to go through clinical trials yet, but the evidence is mounting that it is getting patients through surgery with fewer complications and better prospects of a full fast recovery. I've been in the theatre and watched someone wake up after a 9 hour surgery and instantly be alert enough to say they'd like a cup of tea, which the anaesthetist attributed to the decisions he was able to make informed by the software. It seems as if it has already had an significant positive impact on the health of the people treated by anaesthetists using the software. If further studies support the anecdotal evidence from our users, the software might have a significant impact on millions of people.

I'm building Packj [1] to flag malicious/risky open-source dependencies. It offers “audit” as well as “sandboxing” of PyPI/NPM/Rubygems packages and reports hidden malware or "risky” code behavior such as spawning of shell, use of SSH keys, and mismatch of GitHub code vs packaged code (provenance). We found a bunch of malicious packages on PyPI/RubyGems using the tool, which have now been taken down.

1. https://github.com/ossillate-inc/packj

Potlatch, the user-friendly editor for OpenStreetMap from 2007 to 2013.

I'd been involved in OSM since its first few months (2004) but found contributing intensely frustrating. I wanted something where drawing a road was as quick as it was in Illustrator, which I was used to. Previously you had to create nodes, link them into segments, link those into ways, and manually add tags. Potlatch was a Flash app that allowed you to go click-click-click, choose "residential road" from a dropdown, and there it was - you'd added a road.

I wouldn't for a moment claim it was great code - it really wasn't. But it was the right thing at the right time for OSM. By 2013 people with money were starting to sniff around the project, and Mapbox got paid to build something better and more polished. I was frankly relieved because I'd had enough of defending the newbies against the self-described power users. Still, a significant part of OSM being where it is now is thanks to Potlatch, and I'm proud of that.

cycle.travel is also something to be proud of!

Maintained Spree as it’s community manager (https://GitHub.com/spree/spree) for 2.5-3 years, depending on how you count. Taught me a lot about OSS. Dollar figures processed using code I wrote / maintained hurt my brain. What hurt my brain more was US sales tax rules.

I also wrote quite a few programming books (https://ryanbigg.com/books) and some of the Ruby on Rails guides. These have gone on to teach thousands of people around the world. I really love hearing from those who’ve read my work.

I was the creative co-founder of The Mysterious Package Company (mysteriouspackage.com) and we - gasp - sold mysterious packages. It was a wild idea pitched by my cofounder, to which I was a hesitant buy-in, but the impact we had on people is astonishing.

Rich stories, physical things (letters, puzzles, hair..), and a customized elements are still extremely rare to find in a product offer.

I'm no longer involved (and I didn't get rich), but I'm still proud of the experiences we created for the human bonding that occurred after delivery.

To this day there are people who come up to me saying "You!! I couldn't sleep for a week!" or "You!! My father and I went over your aged documents with a fine tooth comb and they were _REAL_." I'm so proud to have given these people a moment of awe and wonder.

I built and am still currently running a livestream tipping service localized for Indonesian. We need specialized service for this because Indonesians don't use credit card so existing services like Streamlabs is a no go.

I would like to think that it sparked this new cultural phenomenon and made livestream tipping a normal thing.

I am just amazed that something that started as a weekend project can help others tremendously.

Internet infrastructure monitoring, monitors a third of India’s internet backbone, and a 100% of that of Bhutan. In production since 2014.

Python, C/C++, Perl, Celery, Redis, MySQL, Bare Metal.

I don't have one big thing, but several small things that I am proud of having done. I wrote an application to assist in comprehensive cardio and vascular screenings that has been used to [hopefully] save many lives. I wrote an application to process prescription orders using HL7 for a national hospital system to print out shipping labels for their prescriptions. I designed a never implemented system to allow patients to securely control, share and revoke, their medical information between pharmacies, doctors, and other health care providers (if such a system were ever implemented it would have a tremendously positive effect for a lot of people). I wrote a Memcached port for Windows. A couple of libraries to assist other developers. My proudest accomplishment though has probably been mentoring new software developers.

Most of the most consequential changes to the reddit feeds a few years ago I was involved in or directly came up with. The most visible was probably the one that started putting discussion-heavy posts on the front page (things like legaladvice, amitheasshole, askreddit, unpopularopinion, etc). It’s weird to think about the resulting butterfly effects that are completely beyond my knowledge and comprehension.

It's crazy how things have changed. Reddit is now heading in the opposite direction. It's a shame, because I think that your approach was the better one.

Built Video Hub App that almost 5,000 people have purchased. I was a math teacher, became a web dev 6 years ago, built this 5 years ago. Most proceeds go to charity. Very minor by comparison to others, but I'm just starting out ;)

https://videohubapp.com/ && https://github.com/whyboris/Video-Hub-App

What I did that is most impactful is that I've been giving at least 10% of my income to cost-effective charities for over 10 years now (see Giving What We Can - thousands of others do the same). This amounts to almost $100,000 given to charity which translates to thousands of people protected from malaria for many years of their lives.

What was your app build with if you dont mind me asking

It's Electron (Chromium & Node) running Angular. Has FFmpeg under the hood to generate screenshots. The full code is in the repo - see link above :)

Added a "reply" button to Wikipedia discussions; design was later picked up by the Wikimedia Foundation and properly productionized. Probably saved a lot of people some time, because what you used to do was open the source code for the entire discussion, scroll down to find the comment you were replying to, and insert your comment after it in the code.

Not sure if it counts as building something concrete (I have been programming commercially for ~20 years so I'm pretty sure there's something if I dig) but does Stack Overflow impact count? I have over 6,000 answers posted and a calculated reach/impact of over 50 million people. That sometimes makes me smile and feel that I have contributed something.

sharedsolar.org

Back in 2010, I built the software systems to manage solar-powered microgrids providing prepaid electricity in remote, rural offgrid communities with no internet connectivity. People could pay for the electricity service when they wanted and could, with no minimum amounts required; aside from the tech, we wanted to demonstrate a viable, sustainable business model for scaling so free electricity was not the objective.

Constraints for the software system running at the microgrid included - server hardware should not draw more than an energy-efficient bulb at peak load, cost <$100, little-no internet conn in the regions we deploy but remote access required, little-no technical capacity available locally (made things interesting for debug/updates...), integrate with meters + charge controllers + gsm modules etc each speaking potentially different protocols, allow for meter data collection every 1-3 seconds(!) and utilized in distribution + tariff accounting, etc.

Took about 3-4 months to go from concept note to first field deployment in Mali. Over the course of the next couple of years, increased robustness and features and expanded to over 20 villages in East and West Africa (Mali, Uganda). These were all villages/communities that for the first time had homes with AC-electric outlets that they used then for applications like lighting, cell charging, small fans, etc.

My first job out of college I worked for an international telecommunications company.

The first big project I worked on was to develop a call detail record (CDR) search tool.

This tool was used to help locate a missing family who had been lost in the Nevada wilderness for more than 48 hours: https://www.cnn.com/2013/12/11/us/nevada-family-found-alive/...

A statistical technique I developed was incorporated into a number of award-winning spam filters, including SpamAssassin.[1]

I'm also apparently the original inventor of the tracking cookie, which had the implication that no one was able to patent it. It was presented in a patent of mine[2] that was about a collaborative filtering technique for recommending ads; I'd come up with the tracking cookie mechanism to support that technique. So, it didn't attempt to patent the tracking cookie separately; but because it was the first publication describing the method, no one else could patent it either. In 2021 a joint legal brief filed by Google and Twitter together, defending themselves against a patent troll, called it "Robinson's Cookie". My patent is owned by Google now. It contained a lot of details for giving users control of the data derived from tracking; that part was pretty much ignored by people implementing it.

[1] https://www.linuxjournal.com/article/6467 [2] https://patents.google.com/patent/US5918014A

I don't know if this is impactful, but the projecy that reached out to the most people that I can think of is Mil[0]. It is a small stack-based language that I wrote in C as a learning language. I first showcased it on HN, thinking nothing much than to get feedback. It turned out to do decently well in views and reach, even reaching out to the Chinese tech community because someone posted it on a Chinese social website (I forgot the domain name).

Even though Mil's popularity is pretty typical of my other projects, but seeing it going out to other social media is pretty cool.

[0]: https://github.com/HoangTuan110/mil

I built image processing pipelines that have been used to follow patients throughout dozens if not hundreds of large clinical trials.

Apart from that, I built autojump, a command line tool that accelerates navigation in the terminal. This in turn inspired z, zoxide, and other tools.

A funny one is that I asked a few fairly basic questions when SO was still in its infancy. These turned out to have an enormous success. Some are still the authoritative page on the question.

Impactful? Probably CMake policy CMP0053[1]. Improved performance of CMake configures by 30%-50% depending on how intricate the code was.

While not done yet, getting C++20 modules to compile via CMake will probably eclipse that.

[1] https://cmake.org/cmake/help/latest/policy/CMP0053.html

A custom feature-flag system for my current firm. It lets them roll out things unattended ("add 2% of users every day until it's fully on"), gated in ways that fit their business structure.

We're in a space(payments) where deployment is a tightly managed compliance thing, and people get very touchy about specific assumed behaviour. A lot of support inquiries are literally "you just fixed things and got fully certified to be compliant with a third-party service? But we LIKED the old behaviour!"

Feature flags have lowered the tension. We can put sensitive customers into a penalty box until they're ready to use the updated feature, and if something blows up too badly, we just entirely deactivate the change until it can be properly fixed, with a few clicks. Virtually any significant project has one or more flags, and it's ,mostly been a "alternate Fridays are for side projects" sort of task.

Hmm, feel pretty small compared to many here.

Probably most impactful, I wrote the linux driver for HP's (now PMC Sierra's?) SmartArray RAID controllers, of which many millions were sold, most inside HP servers.

Back in 2009-2012, I built a cyclekart[1] in my driveway, and documented it on youtube[2]. Back then almost nobody was building cyclekarts, apart from the original inventors, the Stevensons. Many people have told me my videos inspired them to build their own cyclekarts, (maybe because I succeeded despite obviously not knowing what the hell I was doing) and today there is a thriving worldwide cyclekart community. I don't know for sure how much difference my videos made, but I like to think I had a hand in popularizing the hobby.

In the hobby software world, I made Space Nerds in Space[3], but I don't think that was very impactful, as nobody plays this game because it's too hard to gather together a crew, but as part of making that game, I made gaseous-giganticus[4], which creates textures for gas-giant planets, and has been used by people creating mods for Kerbal Space Program, and I haven't seen a better gas giant texture generator out there yet, despite that there are some obvious (but difficult) avenues to pursue.

[1] https://cyclekarts.com/ [2] https://www.youtube.com/watch?v=QaNHLvHGONc&list=PLcSUyKz3gf... [3] https://spacenerdsinspace.com [4] https://github.com/smcameron/gaseous-giganticus

Once upon a time, I sped up Tornado Web Framework by quite a bit.

I used to write one or two popular Go libraries.

There are (or were?) big McRouter + Memcache clusters behind New Relic. I prototyped that and deployed to prod in ~3 weeks.

I was one of the few engineers that introduced Go to New Relic.

These days I would send small patches to Apache Druid.

Besides Druid work, I can't really say all the cool things I do these days.

Did a lot of work on Wikipedia with media, usability, and internationalization. As with all such things that merely facilitate volunteers, it’s hard to say what’s mine or put dollar values on it. But it’s touched at least a billion lives, and facilitated a large fraction of a media library that will likely outlive me.

I’ve worked on minor stuff that was foundational to Google’s commercial offerings, but I think that isn’t as high impact and probably someone else would have done that as well or better. For the Wikipedia stuff, for good or ill, I owned some of those decisions.

Wikipedia could not work without that sort of work. Same with Open Street Map and all the little contributions to the map. It adds up to a lot.

One of the things I did was helping at a company I contracted at for a few months.

The company did these pdf invoices and the design team would change the design weekly. And there was a junior dev working there and she spent 4 days a week trying to get these new designs into html to generate the invoice and convert to PDF.

She was quite down because she felt like she was missing out on working on stuff she could learn from.

So I went talked to the design team and got them to generate their designs as Adobe forms with named fields.

Then I sat with the dev and we implemented in about 2 hours Adobe form field data and outputting a pdf.

Then each week she got given a new form. Double checked the fields. And then replaced the form.

The weeks that followed she would spend 1 hour a week doing her task and was able to work on the main application and get real work.

Edit: wow people have contributed a lot of awesome stuff. I feel like I haven’t contributed anything now haha. I just picked this particular story because I felt like I helped someone out of a crappy situation.

I worked on a system for querying letters from prison inmates that would allow advocates to detect and respond to abuse by guards or fellow inmates.

While I don't think I had a huge impact compared to other contributions, nor did it scale to billions of users, I like to think that it helped at raise awareness about abuses in a dark corner of the world. It is still in active use.

I was first in, best dressed to write the R API wrapper for an open source server (ODK Central). Proceeded to go through open source peer review at rOpenSci and made it a robust R package that is now used by a good few people.

The package is of course nothing HN worthy, but I'm proud of having contributed something back to FOSS.

The crunchy bit was parsing form data by introspecting a form schema (then XML, now JSON) which initially nearly made me lose my mind, hence the package name "ruODK"?

We are two friends working on a native app to analyze videos using computer-vision [0]. We have been developing it for more than 2 years, to make sure it works in real-time for all CPUs. Not sure about impact but it is really cool to play and analyze videos in real time and help unlock some of the values stored in lot of video libraries. [0] https://ramanlabs.in/static/videointel.html

Hard to say, as they were contributions to existing projects. Those would have happened without me most likely.

- ported numpy/scipy to windows 64 bits, and making sure windows was well supported

- pushing for numpy/scipy to move from svn to git

- wrote a prototype of what would become scikit learn. The project really took off after I stopped contributing though

I do very little coding now, but I had several people I managed go on good careers and thanking me for it. That was maybe in the end the most impactful thing I do, I hope.

In 2012 I was running a Minecraft server for a friend and wrote an initscript to handle it as a daemon, do backups, etc. I threw it up on GitHub and didn't expect anyone to see it. A couple of years later I learnt it was used on commercial Minecraft hosts. Was pretty cool to have built something that other people could tangibly use as income.

I also ratelimited logging in Linux cifs. Now a spammy log message can't hang or panic a client system.

That's probably technically and commercially more impactful but I like my Minecraft script more personally.

Created the first data team in 30yo corporation in 2007-2008 that shifted the company from proprietary to open-source tech.

A cookie store handling over 50B transactions/day for over 1T profiles

The London Olympics realtime (online) video analytics able to handle over 3M streams on 10 servers (physical).

The March Madness realtime online video analytics

The first realtime distributed OLAP cube

Sold then built then launched a financing tech service to a large bank. Bootstrapped :) Never had more than 2 engineers including myself. System is still live.

Honestly, I have built nothing impactful in an 30+ year career. It's mostly been working on my own or other people's ideas that didn't pan out or that I got disillusioned with, or building internal systems that a few dozen people use.

I'd estimate that the vast majority of the code I've written is not running anywhere at all today.

why not find something that you would find rewarding to work on, even if it's on the side? the things i've done that feel impactful are little tools i've made to help the people i know

Honestly, I have lost the motivation. Or perhaps it that I find nothing about computers to be rewarding anymore. I've almost decided that life was simpler and better when everybody was not buried in a phone 12 hours a day and didn't need to be online from home to deal with the basic demands of working and living.

at my current trajectory i'll get to where you're at in 10 years...

It never saw the light of day, but I developed a really cool prototype with WebRTC that allowed our customers to remotely log into another machine. It was basically what google has in this product https://remotedesktop.google.com/. It was one of the few things I worked on where I was genuinely excited to code it up.

My first internship had me and my then flat-mate (he was independently selected for the only other internship spot, neither of us knew about the other’s application, while overseas on Erasmus study, which is uncanny) adding “pay this invoice with online payment” (PayPal/Stripe/…) functionality to a product that handled time-tracking, tax reporting, and invoicing for Freelancers, with a enthusiastic user-base of SMB/sole-traders and a high UX-bar.

It was the number one UserVoice request and we were incredibly lucky to have the entire feature ownership to pair develop (with minimal but stellar oversight from the tech lead) and it had a huge multiplier effect on the product offering overall.

I’m very grateful for being in the right place in the right time and it’s contributed a lot to the “valuable code is the code that your users are benefiting from” lesson that constantly reminds me that book-smarts are nothing without a solid understanding of user needs.

I run https://www.dreamlist.com and it's become a major, if not the top, online gift drive platform in the US. Anyone who knows families in need can organize a gift drive for them. You can add items to lists, lists to groups of lists, to multi-branch organization pages full of items wished by children and families who may not be able to afford gifts otherwise. It's like a Y Combinator for direct giving.

DreamList is free to all participants in the system and I spend a lot of Q4 helping giant drives set up to get just the right gifts to many many thousands of children (some drives support 15-30,000 children in foster care, single parent families, natural disaster situations, or church communities across multiple states, and we support an increasing number of drives). Q1-3 are spent building more functionality to make the next Q4 easier because it is inevitably bigger than the last.

Firefox for iOS and Firefox for Android. Used by tens of millions of people.

Not just me - big team effort. Engineering manager of both.

This probably isn't that impactful on the grand scale, but I want to mention 2 things

On a problem meeting to get better at detecting some SMS fraud, we realized some manual labor the fraud team had to do with Excel. I made a program that automated the checks and presented a resulting ranked list, I saved that team (according to them) around 1 hour a day of boring, stupid work and let them either rest or use that time for better work

I did a small audit on webpage size on my company to see how impactful the changes would be. Approximately 30% to 40% of the page could be reduced. The calculated cost saved was low, $150 to $200 per month, but also around 100kg to 150kg of CO2 released on the atmosphere. If replicated on other pages the total cost saved on both dollars and CO2 could be tripled

While not a lot, I like to think that those small things done everywhere could ne a substantial help on global warming

I built a dirt-simple phone service for people to call and scream[0]. It went viral and got mainstream media attention. My partner was not wild about the hours a day I spent moderating 3-second recordings of random strangers screaming.

[0] Just Scream (https://justscream.baby)

I wrote a Mach-O parser for Homebrew (the macOS package manager) that’s invoked on just about every package install, so that’s probably a couple of million daily users. It also ended up as a dependency of CocoaPods at some point, so it’s on the critical path for a good chunk of the App ecosystem as well.

I also implemented 2FA and API tokens for PyPI (and helped/continue to work on lots of other parts of that ecosystem).

I used to work for Twitch and built the Custom Live notifications for streamers. It was a relatively straightforward change where we just changed the payload of what the streamers wanted the iOS, Android, email notifications to show. There were some behind-the-scenes work where there is actually a language/curse word check and decisions on if we needed to translate the copy to the receivers local language.

The measurable change was a 30-60% increase in the notification CTR and resulted in hundreds of millions of incremental hours watched.

Hmm oddly probably my first “real” full time job is where I had the most impact - I was one of two programmers hired for a summer to redesign a stress testing suite for a server hardware vendor, prime95, cuda-burn, etc. integrated into one single python application to collect the data. I stayed there during the school year part time and the next summer I got to hire another dev (my counterpart left to facebook).

We then worked on a baremetal automation system that worked through IPMI to completely automate the burn in process -remotely starting servers as soon as they got their IP registered, PXe booting them to the burn in image, and then kicking off the testing process. We had a way overkill rabbitmq system to collect streaming logs from every server as they ran, and all orchestrated via rethinkdb change feeds. I think it is still the most complex software project I have done. Basically one python file would launch 7 separate python processes, each their own rethinkdb change feed. This predated docker otherwise it probably would have been 7 docker containers haha.

Right now I'm quite humbled by the number of people who are using Notado[1] to liberate their Twitter Liked Tweets before the collapse that everyone is worrying about.

There are also thousands of people using a tiling window manager for Windows which I originally built for myself and decided to share publicly for free.[2] I still can't believe how popular it has become.

[1]: https://notado.app

[2]: https://github.com/LGUG2Z/komorebi

I built GoJS, which is one of the most popular commercial JS diagramming libraries: https://gojs.net

I built carefulwords, a very fast thesaurus and quote site for inspiration, used by... tens of people a day. Eg: https://carefulwords.com/gift https://carefulwords.com/solitude

I made the site because I was mad that it was hard to type in urls to use thesaurus.com, and because that site fails to focus the cursor in the search box. So I made my own site that did. I mostly made it for myself, me and my wife use it all the time. I am slowly editing down the thesaurus to manageable size.

I built a 12x16 "Goose Palace" barn out of local pine timbers, which taught me timber framing, and taught my tiny baby who turned 2 years old while doing it that this is just the kind of thing that people normally do, build barns in their driveway. Some context: https://simonsarris.substack.com/p/the-goose-palace

Some photos of building it with the baby: https://twitter.com/simonsarris/status/1584169368203956225

I designed my house, and have been writing extensively about that. Maybe this is the most impactful, since photos of it are all over Pinterest and other sites, now. The first post on that: https://simonsarris.substack.com/p/designing-a-new-old-home-...

I am not sure what is most impactful. Maybe ultimately it is building my family.

Probably the 3D animation code I wrote early in my career, which was then used to animate the dinosaurs in "Jurassic Park".

I started an indie side project marketplace in 2014 called SideProjectors.

https://sideprojectors.com

Back then Flippa was probably the only dominant online marketplace for digital businesses.

It’s a big claim I know but I’m proud that the marketplace still is thriving and since then there has been dozens of similar marketplaces popped up. Also in the past few years it’s been so much easier for anyone to start online projects with various nocode tools and all.

Can’t say how impactful it has been, but I’m happy how far it has come.

For 7+ years mustache.java rendered all the web pages and all of the emails for Twitter. It just does the emails now - they switched to React Native for web. I created it to render my 20k user web site.

https://javarants.com/the-ideal-web-application-templating-s...

I wrote a data integration between two internal, siloed tools at a major ISP. This let me build security alerting on social engineering attempts and successful compromises. These se campaigns were using information from other corporate and gov data breaches to access accounts that had not been setup with pins/passphrases, and going for quantity over quality for targets. Anyone was fair game to them and if they couldn't steal money then they'd resell the access and PII to even more unsavory types for identity theft. At the time, if a caller had the account holder's PII, they'd be able make limited changes to the account. Unfortunately, those 'limited' changes were things like forwarding phone or email service. They did pool the data eventually and the alerts continue to be used today to identify compromise and lock email/phone to prevent them from being used for bank fraud. The reduction of financial fraud on normal people was significant. My work kicked off a ton of other initiatives to prevent other avenues of compromise as well. I went from working customer compromise investigations in the scale of thousands a year to a few hundred after implementation. Having clear data of malicious access that couldn't be ignored prompted those initiatives to be seriously funded and maintained. Moving from reactive to proactive on these was very satisfying.

A network of science labs linked to the International Space Station for science centers, museums, libraries, and schools around the world.

Our 10th mission launches next Tuesday on SpaceX-26 cargo Dragon. https://magnitude.io/exolab-10/

Next mission in planning stages Feb 2024.

I built an integration for a charity that processed many millions per year. The money went to support needy folks in an impoverished nation. Children could get sponsors for schooling, food, and orphanages.

The high-impact part comes from the organization and their mission moreso than my contribution to it, but it was also the most technically challenging work I did (shoehorning previous functionality into places it didn't belong and all the fun that comes with that).

It's been about 9 years and I can see that largely, my backend is still running. The site had a facelift since then, though.

This was a fully custom project, with a pretty standard Rails backend. The complexity was mostly dealing with Convio, the CRM / payment processing system from Salesforce for nonprofits.

Three things.

    - beadm -----> https://github.com/vermaden/beadm
    - automount -> https://github.com/vermaden/automount
    - lsblk -----> https://github.com/vermaden/lsblk

All of them for FreeBSD system.

Early in my career at a FAANG, I set out to fix a minor bug in how some labels were displayed in non-Latin scripts and ended up rewriting a small part of the font handling system. Nothing fancy, basically just a hash table lookup.

Ten years later my code lives on in a product used by billions of people, meaning it has been executed trillions of times since, far more than the total sum of all the other code I have written in my career.

The 2nd most used analysis tool on NSANet in response to the 9/11 commission report that the agencies weren't sharing data. https://twitter.com/masonrothman/status/1521407937985404928

Did you work with Bill Binney? I had a chance to meet him once and got the impression he was the go-to "get shit done" guy at NSA around that time. IIRC, he mentioned having a group of contractors that worked with him throughout his career and credited them with his success.

Spyspace and the Mitch Hedgeberg Quote Generator pages were a hoot!

I made a Chrome extension used by 17 people (including me). It adds fuzzy search to the main Old Javanese->English dictionary website. I assume these users are all scholars of some sort. It’s unlikely to be the biggest impact of what I’ve done in terms of numbers, but I hope it may help unlock insights in this under-resourced language.

Software for Navy RDCs - they basically double data entry info during recruit training on a paper in the day, then re enter it into their systems at night in personal time. made a fully offline capable little SPA to track the data and sync it later. saved 100s of hours each cycle. was challenging (pwa talking to soap..) but felt good

then it got pulled, shelved and never saw the light of day but this was after our time as contractors and i never heard why. but it's probably my most meaningful development aside some niche detection and warning sensor products

One of my first developer projects. Was working for a GIS company reverse engineering ancient geospatial databases (and our own). Nothing had foreign keys, there was a "global connection table" that provided many-many-joins, primary keys were strings, etc. Hundreds of tables and thousands of columns.

Most of our days on the data migration team were spent tracking down missing connections between entities, inconsistencies in the data that our clients had found, etc. I took a "find a string in every column" stored procedure and rewrote it as a python desktop app. Once the basic functionality was there I multithreaded it to run each query simultaneously. After that, I provided a graph-layout GUI that the users could click through and build their queries dynamically based on existing connections they'd already found.

No idea if it's still a thing anymore but it was amazing for my team. We went from guessing at relationships between entities because we didn't want to wait for the stored proc to run for hours to knowing which entities had what relationships in minutes. Single best thing I've ever written.

I've created a knapsack ruby gem for CI parallelisation that has over 122 million downloads. Primarily due to the fact, Gitlab is using it.

I spin off https://knapsackpro.com from the knapsack gem and we are helping our customers run fast CI builds.

So far most impactful thing I've built is web app for police in my country. When I had issues with police, I noticed that they used my app to look up my details. It was somewhat funny. Didn't tell them, I don't think they would believe me.

ULPT: would have maybe been a good point to have a backdoor in that app, maybe... or some sort of a filter for your name

Chronolapse

Originally was for the windows folks participating in ludum dare (48hr game dev competition) so that we could easily make timelapses of the development process ( and so I didn't have to look up the ffmpeg command line arguments every time). These were interesting because all games had to be made from scratch in the 48 hours but windows didn't have an easy one liner for it like our linux friends. It grew some simple bells and whistles like cropping, picture-in-picture (it could take a screenshot AND a webcam capture at the same time), and adding audio.

It is terribly, terribly dated at this point (it didn't look great when I released it!) but folks still use it and I get emails from time to time (and a pull request upgrading to python 3 just recently!). I think there were like 50k downloads on google code before they shut that down. It's totally open source and I never marketed it or anything so it was fun to see it featured in some books on indie game dev and some random sites like lifehacker.

The best part for me was all the people who found and used it for things I had never dreamed of - I was sent timelapses of sunrises, custom engine builds, PhD research growing bacteria, construction projects, a ton of digital art, a custom arcade cabinet build, and one guy's year long journey making on very detailed, very cool cyberpunk scene.

I once built a test rig to evaluate the strength of different designs of CNC'd bicycle crankarms I'd made. Basically a weighted sled slammed into the side of a jig mounted crankarm. That was pretty impactful.

Interestingly, I think the most impactful thing I've built is Computer Graphics from Scratch, a book! Teaching people is high-impact and also super rewarding.

In terms of code, probably some stuff that runs on every Android device (although I don't think any of my original, 2013-2014 code is still in use, but the project itself is very much alive)

I built a word exploration site niftyword.com. It is used by around 200K people a month. At it's peak it was used by half a million people a month. It is useful enough for some people that random strangers email when I am careless enough to let it go down :)

Hard to measure, but I would say that from 2001 - 2003 I created an then co-ran the most well known punk rock website in Portugal. This was way before I knew how to code and before facebook events became a thing, so it was a really valueable source of information for the comunnity.

A solution for a major retailer for sportswear where I designed a compact Certificate Authority module for our product that can be used to easily generate TLS Certificate for internal services.

The main benefits for the customer is physical security, the device is built to be savely stored in a safe or at a bank vault when not in use.

It is built in a way which give total control over the keys to the customer so that our support teams managing the services never have to touch a private key and is easy enough to be used by a non-technical employee of our customers.

For the same audience I'm working on replacing the traditional multi-hub-and-spoke VPN we've built over the last few years (around 500 Hubs in Germany + Spokes) with a true End to end encrypted Mesh system with around 2000 wireguard nodes.

Lastly this is something I hope to do in the near future, building out the first cloud strategy, team, infrastucture and procedures for said sports retailer.

Oh I built a Powershell Wrapper around some parts of the Dynect API and a mostly complete wrapper around the tailscale API which is not widely used but made an impacton a handful of people.

At the start of the pandemic I ran a couple of Jitsi Meet instances for people to connect with their close-ones which was used by a low five figur number of people.

I started a project where we 3d printed a few thousand earsavers for wearing A FFP2 mask for for our local school. I think we at least got two school fully supplied and about a thousand pieces where donated to the hospital that saved my life.

A nodejs closed caption converter. I’m not a developer but can get along just fine for most of my projects.

Funniest part was, I open sourced it. Then a few years and an acquisition later the parent company tried to sell us a tool for converting caption files based off my own code.

https://github.com/jasonrojas/node-captions

How did you feel about that from a licensing perspective?

Not trying to bait a copyleft vs permissive argument, I'm genuinely interested.

I'd love to hear more details about how that interaction went!

Many years ago I built some software to allow people with cerebral palsy to use a computer. I did not get paid and it was not used by thousands of people (as far as I know) - but what made it impactful for me was that I got to see the delight of the people who hadn't been able to access a computer and who were then able to access one.

for me, the most impactful thing in terms of users, was introducing graphite/grafana to a large news org.

Before it was all splunk, everything took ages, and you needed to have a degree in weird regex/SQL syntax to get anything useful.

I started showing off graphite/grafana to a few devs. I put some basic CPU/Memory/HTTP request time metrics in. They started putting it in the expressjs layer they had. This meant that any HTTP call was automatically logged, along with CPU memory and anything else they wanted.

By the time I left, splunk was used to do post mortems, and virtually every team had a grafana dashboard, with the Product/buisness owners setting the SLAs/alerts.

A nights & weekends project that has since become a worldwide federated database and software infrastructure.

Took ten years of managing it alone, but it’s been in the hands of a pretty capable team, for the last few years.

It was/is a free project, designed to Serve a pretty challenged demographic. It has turned out to be quite successful, for a number of reasons; many of which have little to do with me, as the new team has taken it to the next level.

It is not hyperbole, to say it has saved lives.

I’m leveraging that infrastructure as a component of the app I’m developing, currently.

I researched & prototyped (in R), and ultimately put into production (C++) a core set of spectral risk analysis analytics that replaced outdated VaR and vol forecasts for an extremely large asset management firm and left immediately afterwards. Technically speaking, guided risk mgmt/investment decisions at the trillion-dollar scale, ran as-is for 8-10 years before being recently re-implemented in some other language.

I've been lucky in lots of ways on what I have ended up working on. I've worked across the sectors but ultimately working on government services has been the most rewarding, which is far removed from being the most enjoyable.

The most difficult but ultimately rewarding was a system that performed checks on people who wanted to work with children or vulnerable adults. I ended up having ultimate responsibility for this being successful which whilst now I can look back on with some pride, I wouldn't attempt again.

Before that I'd rewritten exam appeal systems and been a key developer in the UKs first online student loan offering. I still meet people 20 years on that have to browse my code when reworking those systems/codebase.

Working for banks pays the bills, and I never do subpar work but not something I look back with fondness on, even though I did my share.

I'm a fairly junior engineer at a subsidiary of one of the big 4. Before that, I was at a well-known big box store working on a few different projects.

The most impactful thing I delivered at my previous company was a script that moved all of our team's data from a self-hosted db to something on company cloud that was a lot more stable. The script itself wasn't very complicated (essentially just mongodump and mongorestore), but it made a big impact on ensuring that our team's dataset search tool would continue to be accessible to regulatory compliance folks. In turn, the regulatory people could use the tool to protect the company from getting fined under CCPA, etc.

It made a pretty big impression on me that something incredibly simple like that could make as much financial impact in expectation as that script did. Now when I mentor interns and newer, more junior people, I always tell that story as an example of how high impact can be surprisingly uncomplicated.

Sadly I never/rarely get to see the impact of my code and a lot of the time my contribution is to the team who delivered, so more like a bee colony making the honey. That said I think back to making systems for fire stations and hospitals to help roster their staff. These systems should have gave the staff an easier time swapping shifts and suchlike. I hope it was good for them!

Built a niche ratings and reviews site that grew to 10M visitors a year before I sold it.

I’m mainly proud of the fact that we kept strict separation between revenue ops and content moderation despite a lot of pressure from billion dollar companies to delete reviews they didn’t like. We left lots of money on the table, but fuck those companies.

15 years on, reviews are woven into most websites in the industry and they’re all pretty biased and controlled by the companies we resisted before selling.

This is impressive and hugely respectable at the same time. I'm working on a ratings site using zero-knowledge cryptography, would you mind if I reach out?

A JavaScript app that automated the resolution of half of Twitter’s support tickets. Logic got refactored after a few years, but still used at Twitter. Probably saved Twitter about $10 million a year over the last ten years.

Built the software to process the Positive Train Control data that is fed into the train engine to perform automatic safety control of the train. It's been deployed and running on passenger rail lines. The goal of PTC was for preventing train derailments but can be used for "autopiloting" a train.

GetCalFresh.org. Way easier way to apply for food stamps. Felt good to have left after 6 years going from helping 1 person get help to over a million. Still going strong.

Also lots of strangler pattern iterations! That was fun.

I didn’t even build anything here, just set up an online service. In 2020 I volunteered with a small bail fund serving about 100 clients a year with annual donations of about $40,000 - primarily checks, but increasingly online payments. In May I moved their donation process from an excel spreadsheet manually reconciled with PayPal to a saas donation portal, which managed recurring donors, generated tax receipts, etc. I imported all our existing donor records, set up the option to pay by Square instead, etc, it was great. My notes from choosing the service mention that if we ever hit 12,000 unique donors we would go up a payment level.

Later that month, when George Floyd died and people started protesting, they also donated to bail funds - many of them explicitly to bail out protestors but many plain donations. I think our new donation portal handled over one million donations in two days.

(Our new square account was, for obvious reasons, instantly locked for fraud and we managed to get their support to re-open it within a few hours on a Sunday, they were very responsive! We didn’t keep all the money - there’s a National bail fund coalition and it was very random which funds were shared as donation recommendations, so the massive influx of donations to a few funds was distributed across the country.)

I created a really popular park in a mid-sized city. It’s surreal to see all kinds of people play on it.

Professionally, probably findmyschool.vic.gov.au. Used by hundreds of thousands of parents every year to find what school zone their house is in. Built and maintained almost entirely by me.

Also SchoolScape, an internal department tool used by dozens of public servants to plan which schools need to be built or upgraded. I just coded it, with the hard stuff being done by economists. But from the feedback I get, it has made a huge difference to the people who do that work.

As a hobby, opentrees.org. Definitely seems to have caused some ripples in how tree data is seen and used.

As a Victorian parent who moves house way too often I would like to say thank you.

Hehe, well as with most things built professionally, I can't really take any credit for the concept or even the design, but I do take the responsibility of keeping it up and running pretty seriously.

I don't know how much other government-hosted software you use, but I guess I'm thanking you for the fact that it actually works (and please don't reply that you also worked on the census website :/ )

#1 Computer simulation of automobile emissions testing, that proved more stringent emission standards could be implemented in the state of California.

#2 Space shuttle launch system programming

Worked on software used in cash registers owned by Target, Walmart, the US Postal Service, and various large European and Asian equivalents. Comparing the previous model's UI to the new one was similar to the jump from command line UIs to GUIs, in that they were easier to understand without having to know a bunch of obscure commands. The company did a lot of work to ensure they were also fast to use like the old text-based ones. It really made the obscure cases easier for cashiers with little training to handle.

Probably the thing I feel best about is the museum I made with my son that educates people about how older versions of websites, operating systems, and apps used to look:

https://www.versionmuseum.com/

I don't want people to forget our "technology heritage," if that makes sense.

Sometime around 2010 I made a custom skin for an email notification app called Pop Peeper, it's a recording of my pet duck Carl that was downloaded over 11,000 times: https://www.esumsoft.com/pop-peeper/notifier-skins/#Carl

Just kidding. I was lead engineer on a login page for an Experian identity monitoring remediation product for a major data breach affecting over 20M government employees. Millions of people interacted with my code, kinda cool but everything about that code was very boring.

It's not something I built necessarily but my stack overflow account, which I've only posted on about 100-200 times, says my answers have been viewed by 5.4 million people. Anyone with a stackoverflow account can check this in their profile I believe (for me it is in top right and says 5.4m which I presume is million pageviews on q&a pages I've posted), q&a is incredibly impactful.

https://sfzoning.deapthoughts.com. It changed the conversation about zoning in San Francisco, and lots of politicians and activists now quote the topline stat (apartments are illegal to build in 3/4 of San Francisco).

Nothing groundbreaking. But during my few years in game dev I built a relaxing game that had a spiritual component to it. Was one of my first games so.. plenty of flaws from a game design perspective. But one day I got an email from a player thanking me because the game helped immensely during a difficult time. Made my day... actually, I still think about once in a while. So, I guess you can say it was impactful for one ;)

The thing that puts the title of the reddit link into the reddit URL. Massively boosted our SEO.

At least that's the most visible thing I've done.

BoldContacts: a mobile app that helps elderly people call their friends, families, and caregivers. I wrote it for my folks, and the app is now translated into 60 languages worldwide. All free, open source, pro bono.

https://github.com/sixarm/BoldContacts

I developed a model contest mobile app where models from Venezuela and Latin America can submit their SFW pictures and earn Dash coin as upvotes. Many of those ladies thanked us for giving them a way to earn during the tough times in Latam without having to resort to camming work. I am kind of proud of myself that I gave them an opportunity to survive the pandemic.

ModernTeacher.com - The platform has helped 1000’s of schools modernize learning away from traditional 1900’s style classrooms to a modern blended approach. It’s not just about technology it’s also about curriculum, classroom layout, adaptive learning per child etc.

anyone who does something in the educational space .. that's an upvote from me!

Found a single line of byte code that cost $4M of compute per year.

Please tell us more. This sounds like a good investigative story.

We noticed that one line of byte code was crazy hot. We traced it back to the code, and realized it was a special case fallback.

They were summing 10mb of 8 bit encoded integers, in the 99.5th percentile of traffic, so no one noticed. It was using 10% of fleet compute.

We changed the encoding to 64bit; the data size stayed constant, the 99.5%tile latency plummeted, and I got a bonus. Took a week. My contribution to climate change.

A lot of stuff can hide past 99%.

Some things I built on the side, outside of my day job:

In the late 90's, I sold a command-line SMTP e-mailer for Windows. It was easy enough for folks to integrate e-mail transmission into their systems ... even 16-bit systems since spawning a copy of the shell would allow 16-bit systems to invoke my 32-bit mailer. Lots of folks had used these tools for all sorts of things. I got registration checks and cash from around the world before I started taking credit card payments.

I have an open source command-line MP3 player for Windows that folks still use and incorporate into their systems, JS libraries for node.js, ...etc.

https://github.com/jimlawless/cmdmp3

A warehouse management system of sorts. I spent a long time on the systems passing orders in to take out the human intervention first. On a busy monday the couriers would be collecting at 5pm and the pickers would not have finished the 'next day' orders. A few weeks later it was peak season and they had finished by 9am!

On my last day a picker came over and hugged me and said I had changed their lives. Proudest moment of my career!

It was a bit of Python and SQL and a lot of thought!

During my master's, I took a job in a physics group that works with high pressure time projection chambers for neutrino detection. They have a bunch of simulation and experimental data they wanted to organize and share with colleagues.

I first worked on improving the database (adding indexes, reducing redundancy, etc.). Next, I wrote a Python package to make it easier to interact with the database from the command line and Python, and act as a backend package for a frontend Flask API I wrote to serve the data. Finally, I made a simple website [1] where users can query the data.

It was great because I not only got to help out the people working in the group, but I also contributed to making the data available to other physicists around the world.

[1] https://rwth-aachen.de/gasdb

This is only a personal project. I am building a Twitter graph tool. It created a 2d graph of all of your followers (Up to 20,000 followers), and calculates proximity based on shared followership.

[1] https://twitter.com/Nican/status/1592010109202616322 [2] https://graph.bunnypa.ws/

Definitely styled-components[0].

#257th most starred repository on GitHub, used by millions of developers to ship millions of websites — you've very likely visited websites that are built with it!

[0]: https://github.com/styled-components/styled-components

A while back I made a mod for fallout new Vegas that has around 50k downloads now https://www.nexusmods.com/newvegas/mods/56786/ Recently while watching YouTube I came across the firearms expert reacts guy reacting to fallout new Vegas mods guns. I was surprised to see the mine on a stick made it into that video https://youtu.be/xBMgQH9I8is

Our zero-downtime release process (brainstormed and built with one other dev).

We went from 2-4 hours of downtime for every release to sometimes going over a year between order gap-inducing downtimes.

Some trickery with database views to merge multiple transactional databases, scripts, a script execution structure, and a list of fairly straightforward rules to follow were the only technical parts needed.

It was in prod from August 2005 through March 2022 and likely saved 60-100 hours per year of downtime (annoyance for users and revenue loss for the company).

a couple of algorithms deep in the core infrastructure of Azure: the cluster scheduler for placing VMs (published as "Protean"), and a color-constrained shortest path solver for route planning in the WAN.

amazingly I once failed an interview at Google, despite my abilities. I think because it takes me a while to think before I get anywhere.

I worked on an ad attribution service for a AAA games company and sold my soul in the process. It was neat maintaining a service that had 130m+ hits a day though, never had to deal with scaling like that since. Even neater was it was just two instances in production. Vertical scaling all the way!

As a pandemic project, I started a kids stories podcast with my then 5 year old son. Two years later, it has over 5.5 million downloads and I get letters from parents telling me how the podcast has impacted their kids lives. I actually haven't posted an episode in over a year, and need to get back to it!

In the early days of rails I wrote a monkey punch for Active Record that'd raise a fatal exception if any query lacked a limit clause or returned more than a couple 100 rows. Just a couple lines of obvious stuff, but you wouldn't believe how much impact committing that to a repo back then would have.

Most impactful? Wrote a Slack chatbot that allowed on-call operations engineers to leave their laptops in their cars. The bot could help investigate, diagnose, troubleshoot, and resolve issues ranging from single-site slowness to service outages. It talked to databases, CDNs, caching layers, logging infrastructure, servers, load-balancers, and routers. Access was controlled using a tree permission scheme with user and group permissions. Informational commands were generally left open to all engineers and actions were tightly controlled.

I cofounded a startup (bractlet.com) that uses IoT data, thermodynamic simulations, and other technologies to optimize building energy consumption. We've prevented around 10,000 tons of CO₂ emissions, which equates to many millions of dollars in energy savings.

Shameless plug: we're hiring :)

As part of a team at my last job, I worked on some core features of https://www.salesforce.com/products/experience-cloud/overvie... -- if I'm tricked into a bragging mood I like to say a book got written about it https://www.amazon.com/Practical-Guide-Salesforce-Communitie... The product is still useful to thousands of businesses and transitively their customers, so it's probably the most impact I've made even if it's a shared impact with many others.

Individually, nothing much. Maybe an old python2+numpy re-implementation of a slow matlab script for radar, specifically SAR RMA imaging: https://github.com/Jach/radar_sar_rma I still get the occasional ping about it. A handful of other things have over the years been helpful to a handful of other people, like a hacky jira-to-github-issues migration script, or a simple ranked choice voting counter using scraped web data. That's always nice, but nothing super impactful. I don't mind.

Fun question to reflect on answering! It's all about teamwork! I'm defining "impact" as user count:

About 8 years ago I built (as tech lead) a very simple commenting system that is seen by about a million people a day with several thousand DAUs.

I also made a triple-A cricket video game that was huge in India (batsman and umpire AI, some physics).

Made (as enterprise architect) a mobile banking app for a bank with several million customers.

In my career to date, a web application developed at breakneck speed (3 weeks for functional demo to stakeholders, which included members of CDC on Operation Warp Speed advisory committee) by myself and the CTO at the time to facilitate applications to receive and distribute COVID-19 vaccine in late 2020.

This is when the official option afforded by the CDC was a 7 or 9 page, non-fillable PDF that they expected hospitals, clinics, and your primary care office to print, complete, sign, scan, and return to the public health agency you fall under -- who would then transcribe that into a massive CSV for import into one of their immunization data systems.

The application was demoed before multiple PHAs, ultimately becoming the sole solution for an entire state, and one of the largest PHAs in the world. It has since become a showcase project for ongoing data modernization initiatives within these two large PHAs.

Tens of millions of vaccinations were made possible by this effort, and it's still in use today.

Outside of my career, the persistent browser based game (PBBG) I made when I was 13. Several years before I would enlist in the military myself, I received a message from two players -- brothers, one of which was deployed to Iraq at the time, the other in school stateside -- who were able to maintain a higher degree of connection with one another, given limitations of communication otherwise.

OP, great thread. I always knew there were amazing folks in this community, but it is incredibly inspiring to see the many other responses in this thread.

maybe paid video streaming "one ticket one seat" where one entitlement gets one stream even on a global CDN; tried to take it to realnetworks, they said nobody would pay for video on the internet so i took it to microsoft; we did HBO, Showtime, WWE, together -- turns out people will pay for video on the Internet and various Microsoft tech we collab'd on for 2+ years before release went on to be foundations of online video w/ rights for folks like Netflix

https://news.microsoft.com/2000/02/09/microsoft-unveils-digi...

https://news.microsoft.com/2000/06/12/microsofts-new-digital...

I was leading mobile platform engineering at Walmart when they first merged their Walmart and Walmart Grocery apps into a single app. It was a herculean effort and the resulting product left a lot to be desired, but my work certainly impacted hundreds of millions of people.

My software consultancy developed a surveying system for young people suffering with mental health issues. It was used before their sessions with medical professionals, and helped inform their clinician on their current state, along with overlaying data from previous sessions to help point out patterns and possible risks.

We met with focus groups of young people (and separately, clinicians) in developing the app, and I felt a strong affinity for the entire project. It still gets used thousands of times per day, and I'm glad I could help bring it to life.

I'd always loved building software, but this project showed me it's so much more than technology.

I've worked on numerous medical devices, many startups. From treating cancer, kidney disease, or providing tools for reconstructive surgery.

Nothing hits you in the feels than having customers thanking you for improving their quality of life, or a child thanking you for giving a parent more years of life.

Whats the most exciting medical device technology today? Red light therapy?

Though-provoking Q!

In terms of sheer amount of people affected it's gotta be all those docs I wrote for Chrome DevTools, Lighthouse, and https://web.dev.

The first commercial remote automated Electrocardiogram Analysis Service, receiving ECG data from hospitals throughout US and Canada, and returning English language analysis within 10 minutes. I was lead developer/architect.

Adopted an orphaned open-source project that was still widely used in the genomics community, despite no updates in ~4 years. Used SIMD instructions, careful memory management, and other strategies to speed up most operations by 1-4 orders of magnitude and support the current generation of biobank-scale genome-wide association studies (https://academic.oup.com/gigascience/article/4/1/s13742-015-... ).

I helped build the Linphone app (voip) that Navalny used to out his poisoners.

When I watched this video I was flabbergasted.

Customizable, feature packed read mode that is used by a lot of teachers and people with disabilities: https://justread.link/

Not really relevant anymore, but back in the day, nodebeginner.org did help a lot of people to get into Node.js development I think.

I kickstarted and was the CEO of a non-profit which functioned for about six months as the shadow covid vaccine location data infrastructure for the U.S. during the early months of the 2021 rollout. We worked with Google, the federally-blessed initiative, California, many county health departments, etc.

My best estimate is many millions of Americans were successfully vaccinated as a result of data we sourced, collated, verified and distributed.

The probable magnitude of the impact is thousands of lives saved.

Our tech stack in the early days was a static site generated with Ruby with search results all in a single JSON file filtered by the client in JS, with the backing data store being Airtable. It got more sophisticated over time.

I like to write personal open source projects to learn a language / learn a statistical concept to its core. To learn Python, I build a missing-value imputation package. This one hit it (to my standards) pretty big. 500k downloads so far, but as someone who uses it daily, I’m most proud of the fact that it’s still the best at what it does[1]: https://github.com/AnotherSamWilson/miceforest

[1] according to my personal benchmarking/use cases and anecdotal experience, no promises.

Depends how we want to define impact.

Is it - what is the thing I made that the most people use? A core service within AWS. Very insane scale.

Is it - what is the thing I made that I think will be the most intrinsically "beneficial" to society? Probably https://contractrates.fyi I've done a lot of freelancing myself and there really doesn't seem to be any single community or hub for freelancers that isn't trying to squeeze every last dollar out of them. I'm trying to make a thing that is legitimately helpful and completely free.

Nothing, I have realized nothing I have ever built actually mattered. Some of it made a bit more money, but none was impactful.

It's actually really hard to deal with.

I wrote code to generate the graphic for a decal that gets applied to units in the mobile equipment fleet for Dupont. It's a bit satisfying to drive past a Dupont site and see my work out in the real world.

Also I helped publish a Simpsons themed mod for the video game Doom 2. It's got it's own fan wiki page at this point.

I wrote a pretty popular sequential image downloader in the early 2000s. I suspect it may be the reason why websites started randomizing the filenames of their image assets.

In the 2005 I published a guide (cafes-wifi.com) to 130 cafés in Paris with good free wifi and electrical plug. Tested myself. Made it for my friends, nomad software workers. But quickly became a big success among many nomads workers but also tourists in Paris who needed connexion.

In 2017 The website was closed.

Overall for a decade I had 10.000 unik visitors / month. Impactfull I would say

About 25 years ago, with a group of friends: https://www.srcf.net/

It was what you'd call a community-run webhost, but at a time when such things weren't common. The main innovation was making it easy for multiple people to administer and hand over websites: we'd noticed that student society websites tended to get lost or rebuilt every year, because they were run under people's personal accounts which stopped working when they graduated.

I built an automation on a form for students who have free-time during lunch. Admin wanted some accountability on where students were. The form allows teachers to set limits on the attendance for the room, records names and emails every day and keeps a record of who was signed up to go somewhere on a given day.

helps teachers stay organized and helps keeps the students accountable. Its simple, quick and eliminated paper hall passes etc...

it is small and quiet. But the students use and respect it the admin appreciate the simple records it keeps and teachers like the extra time they get avoiding paper sign ins.

First implementation of CAPTCHA circa 1997

Ironically, there are people here bragging about popular scraping software they wrote back in the day

Though not every use of CAPTCHA intends to prevent or limit scraping -- some sites let you read everything with no CAPTCHA, but apply one if you want to write something (or take an action that affects the outside world somehow).

Security Kit for Drupal: https://www.drupal.org/project/seckit. I built it when I was a junior QA engineer both learning how to program in PHP and doing first steps in the security. I open sourced it, pretty much moved to Ruby and forgot about it just to learn several years later that it's used on 50k websites across the world.

Relationships.

Tech wise, very early Docker and Docker-related integrations with a bunch of other amazing people.

Working now at a bigco, the most impactful thing I do these days is in guiding projects away from building the first thing they think will solve a problem. People don't spend much time doing thought experiments of how changes will evolve in the future or with adjacent scopes. After thinking in that mode for a while you realize that there are concepts here that could and should be separated. A small tweak here and there, changing some naming/terminology goes a long way to saving tons of refactoring/cleanup down the road.

If you mean single-handedly, kinda hard to say. I also rewrote chunks of a retail FX app written in Java1/awt -> Java5+/Swing. Right now I'm enjoying using my own HN viewer (hackerer.news). I'd like to make an SQL-oriented library so people don't have to settle for JPQL/Hibernate--started but not done/promoted.

A recent stroke of luck was working on a small team building buy-online-pickup-instore for thousands/millions of merchants, that completed just before the pandemic hit.

> I'd like to make an SQL-oriented library so people don't have to settle for JPQL/Hibernate--started but not done/promoted.

I'm sure I'm asking this on behalf of many people - any chance of a sneak preview?

I built and launched corona.help in January 2020. Almost nobody expected a pandemic, but somehow I thought it was possible and decided to centralize all Covid cases. Just 2 months later it had over 5 million users daily. Eventually Google and other huge companies started doing the same thing and users tanked.

I built the first version of a Facebook gaming app that, just before I handed it off, was wasting about 475 person-years worth of people's time every day.

2 million users @ 2h/day.

Charitably, it was providing leisure.

I wrote a slack bot for a college club that liked to share music recommendations. We only had the free tier of Slack and were losing old recommendations as the messages were deleted and there wasn't an easy way to listen to all of them at once. I added a bot so that any spotify link sent to the channel is automatically added to a running playlist I own.

I have code running now at work that gets millions of requests a day and I'm not sure it's more "impactful". I'm not sure how many customers would notice or care if it disappeared, but the slack bot broke once and a couple people messaged me pretty quickly to let me know.

For one of the leading database engines, I created the cost model that the database uses to pick between database query plan choices for almost every query (except trivial ones). For that same database engine I led the card estimation team and did part of the design of the cardinality estimation and statistics that powers the cost estimation.

I spent several years writing a book. It hasn’t been published or anything, but creating something from nothing and having it be 100% mine is an accomplishment no other compares to.

I built a WordPress plugin that helps you to generate free SSL certificate using Lets Encrypt. At it’s peak, it was being actively used by 50,000+

[https://wordpress.org/plugins/ssl-zen/]

For personal: Proximity[1], a flash game that ended up being added to hundreds of flash sites and, from the stats I was able to easily find across several popular websites, got up to over 10 million plays after only a couple of years.

For professional: Built a large and involved interactive speech application (IVR) from scratch that allowed hospitals, doctors, etc to call and check a person's health insurance status for a Fortune 100 health insurance company. Was used in over two million calls while I was there and was still being used when I had quit a few years later.

[1]: https://www.newgrounds.com/portal/view/183428

Myself. Came from a dysfunctional family, enormous debt and have survived lots of trauma to reach a decent position + decent net worth.

Way to go stranger internet friend! Glad to see not only that you've overcome what you say you have, but also that it's a point of pride. Keep it up!

For me, it was the second application I ever released, when I was a student at university and still didn't really know how to program properly.

The application was Dash Board[1] for Newton OS, and it only ran on the final generation of Newton hardware (created by Apple, but spun out as a separate company in its final days, before being killed by Steve Jobs shortly after his return).

It "only" sold a few thousand copies. (But it was during the warez heyday, and I am pretty sure there were also tens of thousands of bootleg copies being used, thanks to the registration code generator by "DocNZ" that was widely shared on Hotline back then.)

But that was really pretty great, since the final MP2000/2100 generation of hardware it required was thought to have only sold about 200,000 devices in total.

I have since had a fairly normal software engineer career, and have worked on apps that shipped far more copies, and today I work on customer facing web applications and API SDKs that have more users, and arguably do stuff that is more "important" (e.g. help companies manage large fleets of machines/robots/IoT stuff) than what Dash Board did — which was basically just improve the user interface of the Newton.

But it's 100% clear to me that the magnitude of user impact of Dash Board was much higher than any other thing I've built. People really loved it — I know because hundreds of them actually wrote to us to let us know. (LOL I mean wrote to me "me" — old habits of pretending the company wasn't just one student in his tiny apartment die hard).

Of course, I made more money later, and worked on things that touched a much larger number of people's lives. But "impact" has both X and Y axes. It was the depth of the users' fondness for Dash Board that makes it eclipse everything since. I don't think there are that many chances to just go for "user delight" as the number one metric.

For me, developer satisfaction is a function of that user delight more than anything else.

[1]: http://www.fivespeedsoftware.com/dashboard

[2]: 15 years later, I open-sourced the code and gave it a proper retrospective: https://github.com/masonmark/Dash-Board-for-Newton-OS

I used to work in a CPU/MCU IP company, dealing with embedded linux testing. The flow had been extremely manual and tedious so I created a FPGA Farm for that.

Specifically, a general run-through of a test had involved the following steps - Choose the right type of FPGA - Get a right bitstream from design teams - load the bistream onto the FPGA - Connecting the FPGA to your PC physically and then using OpenOCD - Use gdb as the loader to load Linux image - With a telnetd in the init script, remotely execute the test on that linux after the boot by using expect/libexpect bindings.

With the FPGA farm, many FPGAs were connected to a server, and it provides web interface and APIs so that people could login, claim a board, upload bitstream, attach openocd and expose tty through socat. In other words, the first half of the mentioned steps became remotely doable.

My team did a bit fight and advocation, and soon CXOs bought in and people shifted to use the system. Productivity got higher. Also coincidentally, COVID breaked out, this system further rooted in our culture. It changes how engineers do their work and how sales do demo.

Despite the success, I always have wanted to replace the home made architecture with something like OpenStack with modified plugins. The closest thing I know is OpenStack with Ironic, but it requires PXE, which is impossible for our embedded-case FPGAs. Any hints or suggestions?

Atomic v2 (pending) - OSS Clockwise alternative with fine control and training of AI assist for time blocking & get together w/ 1:many + outside user - this will be impactful

Compared to most of these comments, I've not built anything impactful.

But the software I've written that seems to have gotten most use is SDL-Ball and the FinalKey password manager.

Well, I also built a "digital bulletin board" for a youth org back when PHP was in fashion, it's no longer used, but they used it, and bought minor upgrades for almost 15 years, so I like to think it had a positive impact on that org. They ended up primarily using a booking system that we designed together exactly to fit their needs.

This is nothing compared to others here but I'm happy though:

1. My first and the most satisfying impactful work was a small tool to generate spreadsheets from a form and mail to management. I did this to learn React a bit more and this ended up as an important tool for all contractors in the company. It was used by more than 300 employees and literally everyone knew it was my project and thanked me often for saving their time. The management moved it from heroku to their internal domain and its still in use 3 years after I left.

2. The second one is at the current job where I have made a site that has data from JIRA, Github, some automation for frontend tasks and some for backend tasks with simple button clicks. People use this everyday and has become the first page to look at every day. Planning to make this a new tab screen in Chrome next.

I built https://topstonks.com, it was one of the early sources of information during the meme stock craze, and a primary source for several major news outlets.

I wrote Forth/2, a native code direct threaded Forth for OS/2. Brian Matthewson wrote an excellent manual for it.

FortressOne, a fork of the 1996 Quake mod Team Fortress. Though there are only a few dozen players, for them, and me, the game and the friendships that have built up around it means the world.

I'm one of the co-founders of Hotjar, so a fair bit of the original code was mine. Most of it has obviously been replaced by others after all these years.

I'm equally, if not more, proud of an extremely bad Dig Dug clone I made in Amos Pro as a kid though :). That's what eventually caused me to pursue a career in software development.

I built a content management system back when that meant something like Slashdot instead of Wordpress. It powered many sites but the main one was https://www.coffeegeek.com. It was launched in 2001 and I stopped working on the software in 2007 and it continued to power that site, basically unchanged, until 2020.

I think a 20 year run for a popular website and application was probably most impactful thing I've done.

Holy crap. I feel you. At the same time, I am amazed at the people that gather here. Makes me want to do better.

Hopefully my inspiration lasts longer than a few hours.

A software solution for supply chain tracking under the Dodd-Frank Act Section 1502 aka Conflict Minerals. I like to think that this does not only have a positive impact for the turnover of my (ex-) employer but also on the lives of the people in e.g. DRC.

It was also the first project were I was the lead for the development side of things and also made myself known as the domain expert. Fun times :)

Something small in scale but I am quite happy with it. I work as a game developer and in my last job I added lots of modding features. More scripting features, making more studf moddable, ability to add new ui etc. Things that allow more technical modders to make even more complex mods.

People did a lot of stuff using those, some even surprised me. So all that work paid very well I think

The second generation Web UI of a Series A startup in 2011 that went on to be acquired for $1B in 2020. I have another promising personal project in the works I'm hoping overtakes it.

I built (together with my team) an entitlement service, which makes creating new billing plans a lot easier, and reduced our time to launch in new markets down to just a few minutes.

I wrote about it here https://arnon.dk/why-you-should-separate-your-billing-from-e...

I worked on the epitaxy for vcsels that go into iphones for the facial recognition. Not that impactful but cool to know that the stuff I worked on is in use all around me.

patched tmux to have 24 bit color support

I was tech lead and architect on the system that runs the UK's digital trade remedies platform to control trade tariffs and special measures post Brexit. It's the first and only platform of it's kind. I suppose that's the most "impactful" as it manages events that affect entire industries on a national scale.

I’ve built 15Five, a employee engagement platform. It was an effort of many people working together over many years, and I had the good fortune to be there at the start. Many people use it weekly to communicate with their managers and peers. I’ve seen it deliver a positive connection in remote and on-site teams.

For 10 years until recently a statistics research system that was the primary tool for keeping granular measurements on the health of the US economy.

Is there a place to read more about that?

a system for tracking gas turbine and diesel engine parts, the engines they were installed on, and the ships the engines were in or docks they were stored at for one particular division of the US Navy.

I built a blog in 1999, very small impact, but it was the most impactful thing I've built. I wanted to build a website to be Slashdot for librarians, and it was quite popular for years. I ended up starting my own webhosting business, and changed my entire career path. So it mostly impacted me, but I think there were some small ripple effects.

An on-prem CDN for enterprise level video streaming on LAN/WAN in and geographically distributed branch offices.

Used wowza, nginx, python-flask

I helped build V1 of https://www.balanceapp.com as part of a small team. Meditation is a super crowded space, but it’s a lifestyle habit that I really believe in. Proud that it’s reached a fair number of people, even if it isn’t as well known as the competitors

I've built a platform that helps furniture factory hire workers. Given that the typical factory worker is not that tech savvy, the platform did not see a lot of users, around 5k the last time I checked. Nevertheless some people found job using it. Everything using PHP, MySQL, HTML, CSS and JS.

A library for streaming database interactions including piping a query to a client as a CSV/JSON and running row-wise functions on it as it passes through without ever holding the whole thing in memory. It's well sugared syntax-wise, very easy to learn and battle tested.

I think the most impactful thing I've built for now is an open source project used to auto complete C++ code in sublime text: EasyClangComplete. It does not take over the world, but I've been using it for years along with tens of thousands of people and that's good enough for me.

htts://oikolab.com - it's essentially a weather data api but catering more to anlaysts who need historical data for planning and evaluation.

We provided 30+ years of hourly historical weather data for more than 16,000 locations around the world to a popular website that generates free weather files for architects to do energy modelling. Most architects don't know it but if they use any recently updated weather file, there is a very good chance that it came from us.

i was watching a documentary about The Beatles and at some point their bus driver said something like: 'you should know how to build and dismantle the vehicle you use to hit the road' so i learned how to build my bicycle wheels!

Some FreeBSD code which later found its way on to every OSX/iOS/macOS system.

I solved for decentralization with a Nodejs app, but have no idea what to do with it. No, it has nothing to do with crypto-coins or blockchain.

Not to flex too much, I raised a pretty good couple of kids that I am proud of.

I did enable IPv6 in one ISP of one small country :-)

Country jumped lots of positions in IPv6 adoption

https://sigstore.dev - although its really not true to say I built it. I started it off, but very quickly smarter folks then me jumped on board and really took it to all sorts of new directions.

I built a decentralised ai network, it is more like openAI but like without content policy.

NowPublic, while being a citizenship journalism site had a Katrina missing persons board which was much, much more popular than the site itself ever was.

https://rectangles.app

It's a way of visualizing time differently - 144 blocks, where each block represents 10 minutes of your day.

Built a scheduling system used by my organization and several related organizations. Has been in use for a few years, and is the central scheduling system.

Nothing crazy, but I built a Shopify app years ago that some customers say is “crucial” to running their store.

It’s not making me rich but it feels good knowing it’s legitimately helping people run their business.

When the vaccines were first rolled out, my friends and I made a site that showed PA citizens hospitals and pharmacies near them that had covid vaccines available.

Every week, PA would release a spreadsheet of all places that received vaccines and we would call the places listed to see their availability. We ended up scaling the operation to ~200 volunteers.

There wasn't much on the technical side, though. We had an Airtable where volunteers would update records an a next.js site that displayed the date via Airtable API. We found the Airtable embed to be too complicated/ugly and even though wrangling Airtable API was a huge pain, it was worth

At work: In house tool for helping image computers without interacting with them as much. (I work in IT)

flexboxpatterns.com — I don’t have a way to measure its actual impact on folks, but it’s still kicking around and getting traffic after 7 years.

I wrote a vaccine booking availability scraper that helped double digits of people get a COVID vaccine a few weeks sooner otherwise.

To check my understanding: this is about changing the order of vaccinations rather than speeding up vaccinations right?

I was an SRE (one of a very small team) on Houseparty, a now-shuttered Videochat startup. We saw some good traction, but didn't manage to make the hockey stick continue for long enough and were bought out by Epic Games. I left shortly before them. About a year after that, the pandemic hit, and I was asked to help again as it hyperscaled; Growing 10x our previous peak in the matter of <6 weeks. Millions of people used it to connect with their friends and family in the early and uncertain days of COVID. I put together the cluster and databases that powered all of that.

That's definitely my greatest impact, and the part of my career that I'm most proud of.

Migrate a responsive web app to iOS and Android store without any code changes.

thinking, in the end what had the most impact was not what I built / specified but what I teached - and other built on that knowledge. So the most impactful was a book.

The security architecture for a new aircraft.

I architected and led the team that delivered the Covid vaccine system for a US state government. Hitting that perpetual moving target and deadline was the hardest thing I’ve done so far. It had a lot of technical impact on that state’s department of health, lots of kudos from healthcare professionals and regular people plus won awards from the governor and secretary of health.

I was leading the team that build the software architecture for some of the Covid vaccine production instruments.

I designed and implemented a betting system using those Chinese POS you normally use for credit cards, made a deal with Telco for data packages for more than 10k paid users consuming under 5MB a month for 40 daily transactions.

We end up serving millions of users a month and the system became part of Dominican culture

Made some good money from it, was 21 at the time

Strange, I thought this would be people posting six or so screenshots of source code they’ve recently committed!

Related: What are the most salient lines of code you've written?

I designed a typeface and while small, the impact of bringing joy and productivity to people is greatly satisfying: https://berkeleygraphics.com/typefaces/berkeley-mono/

For some people the most impactful thing they have done in life is create something that makes obscene amounts of money. I designed and built nanoshelters.com to help homeless people secure uninterrupted sleep. I should be worth more than most of you 'money is god' programmers but we live in a world that values how you much money you make rather than how you treat other humans.

I appreciate the good you've done for the world, but isn't that last sentence just a little bit ironic?

I won't speak for the parent comment, and this isn't a critique on you, but I think it's more of a reflection on the reader than an ironic take.

Many would read "I should be worth more than..." as "I should have more money than...", but that's exactly what the parent comment is railing against. In the corporate world, and especially in the startup space, money is often the metric that defines worth. In the parent comment's world, I imagine they would rather that not be the case, and by <some other metric> they would be worth more than these startups/"money is god programmers" that are "only" worth money.

It could've been put a bit more nicely by not implying the reader is a 'money is god programmer,' but otherwise it's a valid opinion, I think.

I understood it to mean "most of the people on this site", and I certainly didn't take it personally.

The irony I understood from the comment is that the metric the commenter suggests should be considered more strongly is how one treats others, and they do so in the same breath as talking down on some group of people, which would probably take a few points off of their value as measured by that metric. The irony, in my mind, does not hinge on whether or not they'd be more valuable than the subjects of their missive but rather on the fact that their actions conflict with their value system.