In this talk from Callstack’s React Universe Meetup in San Francisco, Oskar Kwaśniewski shares hard-won performance insights from the Ultimate Guide to React Native Optimization 2025. If you’re building React Native apps today—and want them to stay fast tomorrow—this is a must-watch.

Packed with practical takeaways, Oskar walks through how to:

• Flatten views for a more efficient native hierarchy
• Use React 19’s new use and useOptimistic hooks
• Avoid FPS drops with JS thread hygiene
• Leverage the React Compiler for automatic memoization
• Actually use RN DevTools to find and fix bottlenecks

You’ll also see common pitfalls with TTI tracking, learn why crypto-heavy tasks shouldn’t live in JS, and hear how a 12% speed boost was hiding in Android builds all along.

What you’ll walk away with:

• Modern tools for debugging and measuring app performance
• Simple tweaks that yield measurable speed gains
• Insight into where performance wins (and losses) really come from