Stale While Revalidate

Applies To:

HTTP LargeThis platform has been optimized to cache and deliver static content (e.g., HTML, CSS, JavaScript, ISO, multimedia, and software downloads, etc.) over HTTP or HTTPS.

HTTP SmallLegacy. If you are currently serving traffic over this platform, then you may continue to do so. However, we recommend that you serve your traffic over our more robust HTTP Large platform.

ADNThe Application Delivery Network platform has been optimized to deliver dynamic content (e.g., login credentials, account information, etc.) over HTTP or HTTPS. Typically, user-specific and database-driven content are served over this platform.

Rules EngineAllows the customization of how requests are handled by our CDN service. It may be used to override the default response provided by an origin server, CDN settings, and the default edge server behavior. - Advanced

This capability requires Rules Engine - Advanced Rules which must be purchased separately. Contact your CDN account manager to activate it.

Category: Caching

Purpose: Improves performance by allowing our edge servers to serve stale content to the requester while revalidationCache revalidation is the process through which an edge server checks the origin server for a newer version of a cached asset. Revalidation is triggered when the TTL for the requested content has expired. takes place.

Configure this feature by specifying an integer value and then selecting the desired time unit (i.e., seconds, minutes, hours, etc.). This value defines the length of time past TTL expiration during which stale content may be delivered.

The following formula indicates the length of time during which stale content may be delivered:

TTLTime to Live. Refers to the amount of time that a cached asset is still considered fresh. Our edge servers will continue to serve a cached version of an asset while its TTL has not expired. An asset's TTL is calculated by the Cache-Control and Expires headers associated with the response sent by the origin server. +

Each stale response includes a Warning response header.

Default Behavior: Revalidation must take place before the requested content can be served.