HTTP registry: ttl
Indicates the response’s remaining freshness lifetime (see, Section 4.2.1) as calculated by the cache, as an integer number of seconds, measured as closely as possible to when the response header section is sent by the cache.
Caching values control freshness, reuse, validation, and visibility across browser, proxy, and CDN layers. ttl is registered in HTTP Cache-Status. Defining reference: rfc9211.
Identifier (http)
ttl
Indicates the response’s remaining freshness lifetime (see, Section 4.2.1) as calculated by the cache, as an integer number of seconds, measured as closely as possible to when the response header section is sent by the cache.
Keep cache keys aligned with response variation, separate private from shared data, and test stale and revalidation behavior across intermediaries.
This registry value is currently marked active by IANA. Follow the defining specification before sending, accepting, or proxying it.
IANA registry: http-cache-status/http-cache-status-names
Registry reference: rfc9211
Sources