Official React and Next.js performance optimization guidelines from Vercel Engineering. Auto-activates when writing, reviewing, or refactoring React components, Next.js pages, data fetching, bundle optimization, or performance-critical frontend code.
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What the file says
# Vercel React Best Practices
Comprehensive performance optimization guide for React and Next.js applications, maintained by Vercel Engineering. Contains rules across 8 categories, prioritized by impact to guide automated refactoring and code generation.
## Rule Categories by Priority
| Priority | Category | Impact | Prefix | Focus |
|:---|:---|:---|:---|:---|
| 1 | Eliminating Waterfalls | CRITICAL | `async-` | Parallel fetches, deferred awaits, Suspense streaming |
| 2 | Bundle Size Optimization | CRITICAL | `bundle-` | Direct imports over barrel files, dynamic imports, conditional loading |
| 3 | Server-Side Performance | HIGH | `server-` | React.cache(), non-blocking after(), data minimization |
| 4 | Client-Side Data Fetching | MEDIUM-HIGH | `client-` | SWR / TanStack Query, optimistic UI, caching |
| 5 | Re-render Optimization | MEDIUM | `rerender-` | Reference stability, context splitting, derived state |
| 6 | Rendering Performance | MEDIUM | `rendering-` | Virtualization, content-visibility, memoization |
| 7 | JavaScript Performance | LOW-MEDIUM | `js-` | Algorithmic efficiency, avoiding work in render |
…
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Source
GitHub
smicolon/ai-kit · 7 stars · license MIT · pushed 2026-09-15 · branch main
API
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