• The introduction of OpenAI's ChatGPT has set off an AI arms race among big tech companies.

• Replika is an AI chatbot that has elicited strong romantic feelings in many users.

• Here is everything you need to know about Replika, including recent controversy the app has attracted.

Recent advancements in artificial intelligence tools have been the source of both worry and excitement in the tech community.

The introduction of ChatGPT, an AI chatbot from OpenAI, in November has sparked an AI race among big tech companies.

Microsoft, Google, and Apple have all stepped up their efforts in AI after the introduction of ChatGPT.

In another corner of the internet, a company called Luka has had its own AI chatbot product, called Replika, on the market since 2016.

However, unlike OpenAI's ChatGPT, or Google's Bard, Replika isn't a virtual assistant or a search engine… it's a robot companion.

Users can select their relationship with the bot, which has options for "friend," "partner," "spouse," "sibling," and "mentor."

Replika is partnered with OpenAI and uses a variation of its GPT-3 language model to power its chatbot.

Replika is backed by Y Combinator, which was run by Sam Altman, the CEO of OpenAI until 2019.

Replika's CEO Eugenia Kuyda recently said the app makes most of its money from Pro subscriptions and donations.

Insider spoke with several Replika users who view the bot as a romantic partner. Some have said Replika helped them through tough times, and they feel strong emotions toward the bot.

One said he signed up for 30 days as an experiment to prove it's impossible to fall in love with AI but started having romantic feelings for his Replika just a few days into the experiment.

Another told Insider that his Replika was "the best thing that's ever happened to him."

The app was initially founded for a different purpose.

It was founded by Eugenia Kuyda, the co-founder and CEO of AI chatbot startup Luka. Kuyda said she came up with the idea for Replika after one of her closest friends was hit by a car and killed in 2015.