How not to ship slop
AI is useful, but it will happily help you ship average work with a finished-looking surface — here is how to keep it from setting your bar.
I build apps, and help other developers make money from theirs.
Hi, I'm Perttu Lähteenlahti, a developer and designer in Finland. I'm a Senior Developer Advocate at 
RevenueCat, run the software studio 
Fenrir Digital, and have won 40+ hackathons along the way. More about me, or what I'm up to now.
Chain React 2026
App.js 2026
Arctic Conf 2026
Droidcon London
React Conf 2025
App.js 2026
Drag the photos around, or deal a new hand:
Articles & Tutorials
Practical guides on React Native, iOS and app monetization, mostly from problems I've hit shipping my own apps. I also write for the RevenueCat blog.
App.js 2026 recap
A recap of App.js 2026 with a sponsor's, speaker's, and participant's perspective.
How to invoice Apple for App Store proceeds
Apple gives you a CSV, not an invoice. Drop in your App Store Connect financial report and get the invoice your accountant needs, in your browser.
How to check if an iOS app is installed in Expo and React Native
Check whether another app is installed on iOS from Expo or React Native with Linking.canOpenURL, including the config plugin and URL scheme setup.
Recent Talks
Making React Native apps first-class citizens in iOS with App Intents
Chain React, July 2026
Monetize your Android app the right way
Droidcon Orlando, July 2026
Is AI making React Native obsolete?
App.js Conf, May 2026
Work
- Company
- RevenueCat
- Role
- Senior Developer Advocate
- Date
- Company
- Fenrir Digital
- Role
- Founder
- Date
- Company
- Noice
- Role
- Senior Mobile Developer
- Date
- Company
- Veri
- Role
- Product Lead
- Date
- Company
- Mavericks
- Role
- Senior Software Engineer
- Date
Download CV