Cache-Control: proxy-revalidate

The shared-cache equivalent of must-revalidate.

proxy-revalidate binds CDNs and proxies to revalidate stale responses; browsers are free to reuse expired content per their own policy.

httpcacheheaderdirectivecdn

Reference (http)

Cache-Control: max-age=600, proxy-revalidate

proxy-revalidate binds CDNs and proxies to revalidate stale responses; browsers are free to reuse expired content per their own policy.

Common mistakes

Using proxy-revalidate when the requirement applies to browsers too; that is must-revalidate.

Sources