caching-revalidation

Caching & Revalidation

Default Behavior

Next.js 15 has specific caching defaults. AI models often get these wrong.

Rules

Server Components - Data Fetching

For dynamic data that changes frequently:

// Force fresh data on every request
const data = await fetch(url, { cache: 'no-store' })

// Or revalidate every 60 seconds:
const data = await fetch(url, { next: { revalidate: 60 } })

Route Segment Config

For pages that must always show fresh data:

// At the top of page.tsx or layout.tsx:
export const dynamic = 'force-dynamic'  // Never cache this page
export const revalidate = 0             // Same as above

For static pages that rarely change:

export const revalidate = 3600  // Revalidate every hour

Server Actions — Always Revalidate

After mutations, ALWAYS revalidate affected paths:

'use server'
import { revalidatePath } from 'next/cache'

export async function createPost(formData: FormData) {
  // ... create post in database
  revalidatePath('/posts')  // ← NEVER forget this
  revalidatePath('/dashboard')  // ← Revalidate all affected pages
}

Anti-Patterns

• NEVER assume fetch() will always return fresh data — check your cache settings
• NEVER forget revalidatePath() after a mutation in a Server Action
• NEVER use cache: 'force-cache' for user-specific data
• NEVER rely on client-side state to show "updated" data after a mutation — revalidate the server cache
• ALWAYS use revalidateTag() for fine-grained cache invalidation when possible