Building in public

Engineering notes

What we learn while building Lima: the bugs that made it to production, the fixes that stuck, and the decisions behind them.

• growthbuild in public

  How Lima reached 25,000 users without a marketing budget

  No paid ads, no PR agency, no influencer deals. Lima grew to 25k active users entirely through organic channels, starting in the Spring Boot community and spreading from there.

  Jul 29, 2026 · 7 min read

• mobileflutter

  Flutter or React Native: what we use and why

  We build Lima in Flutter. Not because React Native is bad. The new architecture fixed most of what was wrong with it. Here's the actual reasoning behind the choice.

  Jul 29, 2026 · 6 min read

• backendperformance

  Lima's Deep ETag Fix: Bypassing Envelope Timestamps for HTTP Caching

  A response envelope timestamp was silently busting every ETag on Lima's hot endpoints. Here's the deep ETag approach that fixed it.

  Jul 22, 2026 · 5 min read

• whatsappbackend

  The Brazilian ninth digit: how WhatsApp silently breaks your phone matching

  Brazilian mobile numbers gained a ninth digit years ago, but WhatsApp still identifies many users by the old eight-digit form. If you match users by phone, this will bite you.

  Jul 9, 2026 · 5 min read