netlify-caching

Set the Netlify-CDN-Cache-Control header on your function response, for example "public, s-maxage=3600, must-revalidate". Dynamic responses are not cached by default, so explicit headers are required for CDN caching.

Import purgeCache from @netlify/functions and call it with specific tags, such as purgeCache({ tags: ["product"] }), or call it without arguments to purge the entire site. Tagged responses are excluded from automatic deploy-based invalidation.

Netlify-CDN-Cache-Control applies only to Netlify's CDN and is stripped before reaching the browser, while Cache-Control is seen by browsers and all intermediate caches. Use both together to cache at the CDN while forcing browsers to revalidate.

Yes, Next.js ISR uses Netlify's durable cache automatically with runtime 5.5.0 or later. The revalidatePath and revalidateTag functions trigger cache purges without manual header configuration.

Common causes include basic auth being enabled, which disables caching site-wide, missing cache headers on dynamic responses, or inconsistent Netlify-Vary headers. Check the Cache-Status response header for HIT, MISS, or REVALIDATED values.

Durable cache is available only for serverless functions, not edge functions. Additionally, the same URL must return identical Netlify-Vary headers across responses, and deploy invalidation is scoped to the deploy context.