How do you improve app startup time (Time to Interactive, TTI)?

Short answer

Use the Hermes engine to run precompiled bytecode, defer initialization of nonessential SDKs to the background, and avoid heavy synchronous storage and network calls while showing the first screen.

Explanation

TTI is the time from tapping the app icon until the screen is fully rendered and interactive. Improve it with an immediate native Splash Screen, avoid large barrel-file imports, and lazily initialize analytics and advertising libraries after the user's first screen is rendered.

Code example

// Defer heavy Analytics SDK initialization until after the first render
useEffect(() => {
  const timer = setTimeout(() => {
    initializeAnalytics();
  }, 2000);
  return () => clearTimeout(timer);
}, []);

Common mistakes

• Performing sequential network requests and blocking the startup UI until the server responds before allowing the app interface to appear.

Follow-up questions

• How do you prevent UI freezes during heavy calculations with InteractionManager?

Sources

• React Native docs — Optimizing JavaScript loading
• React Native docs — Performance Overview