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How to design AI avatar-based chatbot for 30M users: studying Replika
AI, avatars, and mental health
GenAI and Health: how top apps are designed
About 85% of people with mental health issues do not receive treatment, often because of provider shortages. We also can’t ignore the fact that therapy is not always accessible for people with lower incomes.

36% of Gen Zers and millennials reported interest in using AI for mental health.
In this article, I will dive into the psychology and design of AI chatbot Replika, and in the next articles, I will discuss other popular mental health apps using AI. Subscribe and stay tuned for more!
I’m Replika, nice to meet you
Replika is a generative AI chatbot app that was released in 2017.
Replika quickly gained popularity, reaching 2.5 million users in its first year. However, despite this rapid growth, the app struggled to maintain user engagement and retention. Users loved the app initially, but many did not continue using it regularly.

Replika’s team shifted their approach by focusing on validating product ideas before development. They engaged high-need customers to test concepts through no-code storyboards.
In 2024, Replika’s CEO, Kuyda, reported that the total number of users had surpassed 30 million.
Replika’s target audience
The app primarily serves users aged 35 and older, contrary to assumptions that it would attract younger audiences.
Interesting fact:
Male users outnumber female users by a large margin.