React Native Performance

What the source does

• FilesystemNone observedNo reads or writes in the source
• NetworkNone observedNo outbound calls in the source
• ShellNone observedNo commands run in the source
• DependenciesPinnedNothing floats
• SecretsNone foundNo keys in source

Five audit layers

Gates applied: no behavioural pass.

Audit 0.4.1 · source sha 6f5be687a268 · 14 Oct 2026Report an issue or request a re-scan

• PublisherHoangNguyen0403 GitHub userOwner of the repository this skill is read from
• Source folderHoangNguyen0403/agent-skills-standard/skills/react-native/react-native-performanceThe exact folder we audited
• LicenceMITAs the repository states it
• Commit pinned for this verdict6f5be687a268A new audit runs when the source changes
• Repository statusNot archivedPushed today
• Sandboxed runNot runSkills are read, not executed; layer L4 is skipped

Its description: Optimize React Native rendering for smooth 60fps mobile experiences. Use when optimizing React Native app performance, reducing re-renders, or fixing frame drops.

---
name: react-native-performance
description: Optimize React Native rendering for smooth 60fps mobile experiences. Use when optimizing React Native app performance, reducing re-renders, or fixing frame drops.
metadata:
  triggers:
    files:
    - '**/*.tsx'
    - '**/*.ts'
    keywords:
    - FlatList
    - memo
    - useMemo
    - useCallback
    - performance
    - optimization
---
# React Native Performance

## **Priority: P0 (CRITICAL)**

## Tune FlatList for 60fps

- **`windowSize`**: **Reduce to 5-10** for memory-heavy lists (default 21). **`initialNumToRender`** should cover first viewport.
- **`getItemLayout`**: Provide for **fixed-height items**. Skips runtime measurement.
- **`removeClippedSubviews`**: Enable for **Android** (default true) to offload clipped items.
- **`maxToRenderPerBatch`**: Limit to **5-10 items per frame** to prevent JS thread blockage.
- **`keyExtractor`**: Use **stable unique IDs**, never array index.

See [optimization guide](references/optimization-guide.md) for FlatList configuration examples with `getItemLayout`, `windowSize`, and memoization patterns.

## Accelerate Core Rendering

- ** Engine**: Ensure **Hermes engine** enabled (default in 0.7x). Verify via `global.HermesInternal`.
- **Animations**: Use **Native Driver (`useNativeDriver: true`)** or **Reanimated 3** for GPU-accelerated 60fps animations.
- **Re-renders**: Use **`React.memo`** and **`useMemo`** for expensive props. **Profile via Flipper** (React DevTools) for flamegraphs.
- **Network**: Batch API calls. Use **React Query/Zustand** to prevent unnecessary screen refreshes.
- **Images**: Use **`react-native-fast-image`** for caching and priority. Avoid large PNGs; use **WebP**.

## Reduce Bundle and Startup Time

- **Hermes**: Enable for faster startup (default in RN 0.70+).
- **Tree Shaking**: Remove unused imports.
- **ProGuard/R8**: Enable code shrinking on Android.
- **Lazy Screens**: Use `lazy` prop for stack screens (enabled by default).

## Anti-Patterns

- **No ScrollView for Large Lists**: Use FlatList.
- **No Inline Styles**: Use `StyleSheet.create` (optimized).
- **No console.log in Production**: Strip with babel plugin.

## References

See [references/optimization-guide.md](references/optimization-guide.md) for FlatList configuration, memoization rules, and bundle analysis.

## Canonical response anchors

When this skill applies, preserve the following domain terminology or equivalent concrete examples in the answer when relevant:
- Android
- Provide

Excerpt, first 2,509 characters of SKILL.md, verbatim from the audited commit. It is text from someone else’s repository, quoted so you can judge it before your agent reads it.

npm install -g source-map-explorer
npm install --save-dev babel-plugin-transform-remove-console

git clone https://github.com/HoangNguyen0403/agent-skills-standard
git -C agent-skills-standard checkout 6f5be687a268

Works in

1. 2026-10-14
   ✓SAFE B 89 / 100

   first audit · source 6f5be687a268

Questions about React Native Performance

• github.com/HoangNguyen0403/agent-skills-standard/tree/develop/sk — the audited source at commit 6f5be687a268 and every finding aboveObserved · 14 Oct 2026

Spotted something wrong? Report a correction · Methodology