I’m very interested in Cloudflare support for this but will be forced to migrate to Fastly if it’s not possible.
Question What is the proper way to ALWAYS serve stale content, but have the Cloudflare cache update in the background?
I’ve written a lengthy SO post about this, but the crux of the issue is which Cache-Control/Surrogate-Control headers to use to ensure the CDN cache layer is always refreshed asynchronously in the background while stale content is served to users.