Edge-Cache-Tag
Akamai reads purge tags from the unofficial Edge-Cache-Tag response header: an origin lists comma-separated tags on a response, the edge indexes the stored object under them, and a purge request naming a tag removes every tagged object at once. The same header appears in crawl data from HubSpot-hosted sites, mirroring their Cache-Tag values.
Usage
Tag-based purging solves the invalidation half of Caching: a product photo referenced by fifty pages gets one tag, and one purge call clears all fifty. Akamai documents Edge-Cache-Tag as the header carrying those tags, with tags treated case-sensitively, read from the first header instance, and limited in count and length per response. The origin strips nothing itself: the header travels to clients unless the property removes it.
Observed traffic adds a second sender. Crawled HubSpot-hosted blogs and sites emit Edge-Cache-Tag beside Cache-Tag with byte-identical values on the same responses, covering both CDN vocabularies with one tag set.
Values
Comma-separated opaque tags. The dominant observed
values follow HubSpot's object-ID convention, with
prefixes naming the object type: P- for the
portal, SS- for the site, CT- for the content
object, W- and CW- for widgets, PGS-ALL for
site-wide page settings, and SW- for a settings
version.
Example
A HubSpot-hosted page tagging the response with the portal, site, and settings objects the page depends on. Editing any of the referenced objects purges the page by tag.
Edge-Cache-Tag: P-20927937,SS-58645295751,PGS-ALL,SW-3
Observed in the wild
Crawl data records the header on 41 hosts, nearly all HubSpot-hosted, with every observed value matching the paired Cache-Tag header on the same response.