stale-while-revalidate

Category: Network / Connectivity
Type: New or changed feature
Status: Enabled by default (Chrome 75)
Intent stage: Prepare to ship

Breaking change: No
Enterprise impact: None
Spec maturity: Working draft
Web Platform Tests: No

WPT details: https://wpt.fyi/results/fetch/stale-while-revalidate?label=master&product=chrome%5Bexperimental%5D&product=edge&product=firefox%5Bexperimental%5D&product=safari%5Bexperimental%5D&aligned

Summary

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.

Standards & signals

Specification: https://whatpr.org/fetch/853.html#concept-stale-while-revalidate-response
Firefox: Shipped/Shipping
Safari: No signal
Web developers: Positive
Tracking bug: https://code.google.com/p/chromium/issues/detail?id=348877

Ecosystem

Web Platform Tests: https://wpt.fyi/results/?q=fetch%2Fstale-while-revalidate
Chrome Platform Showcase: https://chrome-platform-showcase.paulkinlan-ea.deno.net/features
GenDN reference: https://gendn.paulkinlan-ea.deno.net/features
chrome.dev demos search: https://www.google.com/search?q=site%3Achrome.dev+stale-while-revalidate
MDN Web Docs: https://developer.mozilla.org/en-US/search?q=stale-while-revalidate
Baseline status: https://webstatus.dev/?q=stale-while-revalidate

Explainers: https://web.dev/stale-while-revalidate/

View on chromestatus.com