The stale-while-revalidate attribute is used by the Cache-Control header and defines an extra window of time during which a cache (proxy, user agents) can use a stale asset while it revalidates it asynchronously. This improves subsequent page load latencies as stale assets are non longer in the critical path.


Specification link

Specification currently under development in a Working Group

Status in Chromium


Enabled by default (tracking bug)

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.


Intent to Prototype url

Intent to Prototype thread

Last updated on 2021-12-13