As developers, we always push our limits to test our applications before they go live. As we all know, no matter how far we test, runtime issues are inevitable. Therefore, monitoring every aspect of the application is a must.

This article will introduce 5 different tools to monitor the web application frontends live in the user’s browser.

TL;DR

1. LogRocket — Replay What Happened

LogRocket provides a JavaScript SDK for frontend monitoring which intercepts actions in the browser and sends them to a remote server.

The most dominant feature in LogRocket is its ability to record all user sessions, enabling the developer to playback the sessions and track every step of the user that led to an error.

LogRocket also keeps track of JavaScript errors in the application and reports the error’s details, including the impact on the connected systems, the stack traces, and user sessions where the error occurred. Therefore, it allows the developer to prioritize the bugs and fix the critical ones.

Apart from explicit code errors, LogRocket can track problems like:

• User Interface glitches
• Broken interfaces
• Slow performance
• Network failures, etc.

LogRocket can be easily integrated with popular frontend frameworks such as React, Angular and issue trackers such as Sentry, GitHub Issues, and Trello.

If you wish to get started with LogRocket, there are 3 plans to choose from: developer, team, and professional. The developer plan is the free plan, and it allows 1,000 sessions per month and 30-day data retention, while the team plan costs you 99 USD per month for 10000+ sessions. The professional plan allows you to customize the features according to your needs.

2. Datadog — The Complete Suite

The Datadog provides end-to-end tracing from the frontend to the databases connected to it without sampling. It enables developers to search and analyze 100% of logs and traces live over the last 15 minutes and retain errors and high latency traces automatically for 15 days.

We can use its continuous profiling to measure the application performance at the code level, which allows us to trace the users, pages, or countries facing the slowest responses and find the lines of code consuming the most CPU or memory.

It’s a tool that covers all the aspects of application monitoring, including frontend, backend, database, and even the test executions.

Datadog also supports synthetic browser tests to automate user experience monitoring by recording multistep browser tests within minutes. Once a test is created, it automatically detects the changes using machine learning and updates the tests accordingly.

As one of the leaders in this area, Datadog is used by several famous companies like Medium, Facebook, and Spotify.

It also includes 3 pricing packages, including a free plan. However, I would recommend you to go with the Pro($15 for 1 host per month) or Enterprise ($23 for 1 host per month) plan to get the maximum use from Datadog.

3. Sentry — Focusing on Errors

Sentry is a full-stack error tracking SDK that optimizes the web application code and performance by monitoring and responding to bugs and crashes in real-time.

Sentry focuses on exceptions (application crashes) rather than informational errors.

Sentry gives a full graphical overview of the errors in the application with details such as the number of users impacted, the call stack, the browsers affected, and the commit that caused the bug.

The tool creates visibility to developers on new issues, regressions, and whether a problem is resolved in the latest release, predicts the commit which caused an issue, and receives email notifications when the code gets deployed using the release tracking feature.

It supports over 17 languages and 29 frameworks and libraries, including JavaScript, Python, React, Angular, and is being used by many organizations such as GitHub, Disney, Reddit, and even Datadog.

The most exciting fact about Sentry is that it has a free developer version that supports all languages and the release tracking feature. Paid versions with more features are available for teams($26 per month), businesses ($80 per month), and enterprises(custamizable) that have free trials.

4. Azure Application Insights — Best for Azure

Azure Application Insights comes as a feature of Azure Monitor provided by Microsoft Azure. It is extensible using the SDK or using the Application Insights Agent.

For frontend monitoring, you can integrate its JavaScript SDK into your application. However, one limitation I see is the support for popular libraries and frameworks, where you have to ensure that you use it correctly.

This tool can monitor the live application and detect performance anomalies with request rates, response times, and failure rates. Using the aggregated statistics and the stack traces provided, the developers can also analyze the server and browser exceptions reported.

Once a problem is detected, it facilitates correlating the failures with exceptions, traces, and dependency calls and examining the profiler, stack dumps, and trace logs.

The Application Insights feature in Azure Monitor is billed based on the volume of telemetry data the application sends and the number of web tests that run on the application. The telemetry data is billed per Azure Log Analytics data ingestion rates.

5. Rollbar — Continuous Code Improvement

Rollbar is an agentless error monitoring tool for frontend, backend as well as mobile applications.

With Rollbar, errors can be automatically logged as tickets in tools like Jira by setting up automated issue tracking, assigning to owners directly within Rollbar.

Rollbar’s real-time feed of errors enables the developers to address the critical errors affecting key customers occurring at low initial frequencies, which are otherwise difficult to detect.

With the integration of tools like GitHub or Bitbucket, Rollbar automatically starts identifying the recent deployment, which may have caused an error linked to source code, stack trace and the commits. This enables the developer to identify and view the differences quickly.

Rollbar provides AI-assisted workflows which enable the developer to take immediate action on errors before they impact users. It presents data like the number of customers affected by the error, the type of platforms or browsers affected, and whether similar errors have occurred before or if a solution already exists.

The automation-grade grouping feature automatically groups similar errors to reduce noise. The grouping rules can be easily customized, or errors can be manually merged to keep the alerts relevant.

Many leading developers and enterprises such as Adobe, Uber, and twitch use RollBar, and it provides SDKs for many languages and frameworks, including Node.js, Angular, React,Vue.js, .NET, Ruby, and Python.

Rollbar offers 4 pricing plans as free, essential, advanced, and enterprise, where the free version comes with 5000 free error events per month while other plans allow you to customize according to your need.

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