React Native Performance Issues Persist After New Architecture

Most React Native engineers gets this wrong. 😃 React Native removed the bridge. Most apps are still slow. So what’s actually going on? With the New Architecture (JSI, Fabric, TurboModules), we now have: → Direct JS ↔ Native communication → Less serialization overhead → Faster module calls But performance issues didn’t disappear. They shifted. 👉 The real bottleneck now is rendering + thread contention, not the bridge. What I see in most production apps: • Too many components re-rendering unnecessarily • Heavy logic still running on the JS thread • Animations not fully offloaded to the UI thread • Large lists without proper virtualization • Poor state boundaries causing cascading updates The mistake: People upgraded React Native but didn’t upgrade how they think What actually matters now: → Render isolation (stop global re-renders) → Thread ownership (JS vs UI vs Native) → Work distribution (don’t overload JS thread) What worked for me: • Treat components as render boundaries, not just UI blocks • Move animations + interactions to Reanimated (UI thread) • Keep state as local as possible • Break down heavy screens into smaller, isolated units Result: ~40% performance improvement instantly) The New Architecture didn’t make performance easy. It made bad decisions more visible. #reactnative #mobileengineering #performance #softwareengineering #fullstack

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