# React Server Components (RSC) vs. Client Components
Understanding boundary placement between Server Components and Client Components is critical for Next.js app performance.
## Rules of Thumb:
- **Default to Server Components**: Keep data fetching, database access, and static UI on the server.
- **Use Client Components Only For Interactivity**: State hooks (`useState`, `useEffect`), event listeners (`onClick`), and browser APIs.
Engineering
React Server Components vs. Client Components: Best Practices
When to use 'use client' directives in Next.js App Router for optimal bundle size and interactivity.
Lalit Kumar
Author
Jul 11, 2026
5 min read
#React#Server Components#Next.js#JavaScript
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