Next.js App Router Caching — Cheat Sheet

Next.js caches at multiple layers. This guide compresses the official caching docs into a quick reference.

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1. The Cache Layers

• React Request Memoization
  • Deduplicates repeated fetch calls during a single render.
  • Cleared after render; not persistent across requests.
• Data Cache (server, persistent)
  • Stores fetch results across requests.
  • Controlled by cache and next.revalidate.
  • force-cache → uses it.
  • no-store → skips it.
  • next.revalidate → ISR-style time-based revalidation.
  • Can also revalidate on-demand (revalidateTag, revalidatePath).
• Full Route Cache (server)
  • Stores rendered RSC/HTML for static routes.
  • Invalidated when data revalidates or on redeploy.
  • Dynamic routes skip this.
• Router Cache (client)
  • Stores prefetched RSC payloads for <Link> navigations.
  • Cleared by router.refresh() (client-only).

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2. Controlling Caching

fetch options

// Always cache (default for static)
await fetch(url, { cache: 'force-cache' })

// Never cache (dynamic)
await fetch(url, { cache: 'no-store' })

// ISR (revalidate every 60s)
await fetch(url, { next: { revalidate: 60 } })

On-demand revalidation

import { revalidateTag, revalidatePath } from 'next/cache'

// Inside server action or API route
await revalidateTag('products')
await revalidatePath('/dashboard')

👉 In a Server Action, this also clears the client Router cache instantly.

Route-level config

// Opt out of Full Route Cache (force dynamic render)
export const dynamic = 'force-dynamic'

// Skip all caches
export const revalidate = 0

// Default all fetches to no-store
export const fetchCache = 'default-no-store'

Also: using cookies() or headers() in a route marks it dynamic.

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3. What Invalidates What?

• Data revalidation (time-based or on-demand) → updates Data Cache + invalidates Full Route Cache.
• Redeploy → clears Full Route Cache (not Data Cache).
• router.refresh() → clears only the client Router Cache.

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4. Browser vs Server fetch

• In browser → cache controls the HTTP cache.
• In Next.js server → cache controls the Data Cache behavior.

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5. Defaults

• Static rendering: Data Cache + Full Route Cache enabled.
• Dynamic rendering: fetch runs every request.
• <Link prefetch> populates Router Cache automatically.

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6. Quick Decision Table

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⚡ Use no-store for truly dynamic, revalidate for ISR, and revalidateTag/Path for precise invalidation. Combine with route config to balance freshness vs performance.