I build stuff.

Hi, I'm Perttu Lähteenlahti — a developer and designer based in Finland. I've spent the last decade designing and building digital products, from mobile apps to web platforms. I also won 40+ hackathons along the way.

Currently, I work as a Senior Developer Advocate at RevenueCat, where I help developers build and monetize their apps. My focus is on React Native, cross-platform development, and making in-app purchases less painful. You can read more about me, or see what I'm up to now.

What I write about

I write practical, production-focused guides about React Native, iOS and Android development, mobile performance, and app monetization — especially subscriptions and in-app purchases. Most articles are based on real issues I've hit while building and shipping apps in production.

Articles & Tutorials

I write about React Native development, mobile app monetization, in-app purchases, and lessons learned from building products. Here are some of my recent posts.