openai/netlify-caching

Caching on Netlify

Default Behavior

Static assets are cached automatically:

• CDN: cached for 1 year, invalidated on every deploy
• Browser: always revalidates (max-age=0, must-revalidate)
• No configuration needed

Dynamic responses (functions, edge functions, proxied) are not cached by default. Add cache headers explicitly.

Cache-Control Headers

Three headers control caching, from most to least specific:

| Header | Who sees it | Use case | |---|---|---| | Netlify-CDN-Cache-Control | Netlify CDN only (stripped before browser) | CDN-only caching | | CDN-Cache-Control | All CDN caches (stripped before browser) | Multi-CDN setups | | Cache-Control | Browser and all caches | General caching |

Common Patterns

// Cache at CDN for 1 hour, browser always revalidates
return new Response(body, {
  headers: {
    "Netlify-CDN-Cache-Control": "public, s-maxage=3600, must-revalidate",
    "Cache-Control": "public, max-age=0, must-revalidate",
  },
});

// Stale-while-revalidate (serve stale for 2 min while refreshing)
return new Response(body, {
  headers: {
    "Netlify-CDN-Cache-Control": "public, max-age=60, stale-while-revalidate=120",
  },
});

// Durable cache (shared across edge nodes, serverless functions only)
return new Response(body, {
  headers: {
    "Netlify-CDN-Cache-Control": "public, durable, max-age=60, stale-while-revalidate=120",
  },
});

Immutable Assets

For fingerprinted files (hash in filename):

# netlify.toml
[[headers]]
for = "/assets/*"
[headers.values]
Cache-Control = "public, max-age=31536000, immutable"

Cache Tags and On-Demand Purge

Tag responses for selective cache invalidation:

return new Response(body, {
  headers: {
    "Netlify-Cache-ID": "product,listing",
    "Netlify-CDN-Cache-Control": "public, s-maxage=86400",
  },
});

Purge by tag:

import { purgeCache } from "@netlify/functions";

export default async () => {
  await purgeCache({ tags: ["product"] });
  return new Response("Purged", { status: 202 });
};

Purge entire site:

await purgeCache();

Responses with Netlify-Cache-ID are excluded from automatic deploy-based invalidation — they must be purged explicitly.

Cache Key Variation

Customize what creates separate cache entries:

return new Response(body, {
  headers: {
    "Netlify-Vary": "cookie=ab_test|is_logged_in",
    // Other options: query=param1|param2, header=X-Custom, country=us|de, language=en|fr
  },
});

Framework-Specific Caching

Next.js

ISR uses Netlify's durable cache automatically (runtime 5.5.0+). revalidatePath and revalidateTag trigger cache purge.

Astro / Remix

Full control over cache headers in server routes. Set Netlify-CDN-Cache-Control in responses for CDN caching.

Nuxt

Default Nitro preset handles caching. ISR-style patterns use routeRules with swr or isr options.

Vite SPA

Static assets are cached by default. API responses from Netlify Functions need explicit cache headers.

Debugging

Check the Cache-Status response header:

• HIT — served from cache
• MISS — generated fresh
• REVALIDATED — stale content was revalidated

Constraints

• Basic auth disables caching for the entire site
• Durable cache is serverless functions only (not edge functions)
• Same URL must return identical Netlify-Vary headers across responses
• Deploy invalidation is scoped to deploy context (production vs preview)