Pi Lens App: 0 to 400K downloads

In short: As Product Manager at PhysicsWallah, I took Pi Lens App, India's first YouTube-layer learning app, from 0 to 400K+ downloads and lifted its Play Store rating from 4.3★ to 4.7★ by rebuilding onboarding and improving AI answer quality.

An idea that lives on YouTube

I'm Gautam Kumar. Students already learn on YouTube, but a video alone doesn't give them notes, practice or answers. Pi Lens changes that: it adds notes, previous-year questions (PYQs), quizzes and AI answers on top of any educational YouTube video, on Android and as a Chrome extension. It is India's first YouTube-layer learning app.

Owning everything

As its Product Manager I owned every feature, release and metric: the roadmap, AI answer quality, onboarding and retention, Play Store and Chrome Web Store growth, and launch content.

Fixing the first five minutes

The biggest retention gain came from rebuilding onboarding, so a new student sees the value of Pi Lens on their very first video instead of having to discover it. Day-7 retention went up.

Earning trust with better answers

For a learning product, a wrong answer costs more than no answer. AI answer accuracy started at 75%, and improving it was core to earning trust. That trust shows up in ratings: the Play Store rating rose from 4.3★ to 4.7★.

Becoming the face of the product

I script, record and present the Pi Lens App launch and how-to videos on my YouTube channel myself, so students hear about the product from the person who builds it.

A weekend prototype that made the roadmap

Brain Games started as a prototype I vibe-coded on my own, and it made it onto the Pi Lens App roadmap.

Where it stands

0 → 400K+ downloads across Android and Chrome, a 4.7★ rating, and a product students use on top of the videos they already watch. More on the Pi Lens App case study.

Quick answers