What is the CDN-Cache-Control header?

CDN-Cache-Control is a targeted cache-control header, defined in RFC 9213, that applies only to CDNs. It uses the same directives as `Cache-Control`. A CDN that supports it uses its value and ignores Cache-Control and Expires for that response, while browsers keep following Cache-Control.

Cache-Control: max-age=60
CDN-Cache-Control: max-age=86400
Cloudflare-CDN-Cache-Control: max-age=3600

RFC 9213 lets each cache keep a target list, an ordered set of fields it reads, such as a vendor-specific field first and CDN-Cache-Control second. The cache uses the first valid, non-empty one, and falls back to Cache-Control if none is valid.

• Vendor fields include Cloudflare-CDN-Cache-Control and Netlify-CDN-Cache-Control. Vercel also reads CDN-Cache-Control.
• It is a clearer way to split edge and browser lifetimes than `s-maxage`, which every shared cache, including corporate proxies, reads.
• Directives keep their meaning: `no-store` and no-cache still make max-age inoperative.

A long edge TTL is safe when you purge on deploy and warm the cache right after.

Some CDNs add their own variant, such as Cloudflare-CDN-Cache-Control, Vercel-CDN-Cache-Control or Netlify-CDN-Cache-Control. See the Cloudflare, Vercel and Netlify guides, and the Top 10 CDNs comparison.