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Rank 6 of 10 on caching criteria

Akamai CDN caching guide

Akamai Technologies · reviewed against the vendor documentation listed below

How Akamai caches: Pragma debug headers and X-Cache codes, Property Manager TTLs, Fast Purge by URL, CP code or tag, prefresh and Tiered Distribution.

Part of the Top 10 CDNs in 2026 comparison. New to the topic? Start with why cache warming matters.

Caching at a glance

Cache status on the response
Not on by default. Send Pragma: akamai-x-cache-on to get X-Cache (TCP_HIT, TCP_MISS, TCP_REFRESH_HIT, TCP_REFRESH_MISS, TCP_REFRESH_FAIL_HIT, TCP_IMS_HIT, TCP_NEGATIVE_HIT, TCP_MEM_HIT); akamai-x-get-cache-key returns X-Cache-Key.
TTL controls
The Caching behavior in Property Manager is the main way to set max-age. Origin Cache-Control and Expires are honored only when you enable it; with both max-age and s-maxage, Akamai uses s-maxage. The Akamai-specific Edge-Control header is generally deprecated.
Purge
Fast Purge by URL or ARL, CP code, or cache tag (Edge-Cache-Tag header, up to 128 comma-separated tags). Invalidate is the default and most popular method: the next request revalidates with If-Modified-Since. Delete removes the content and can add more origin load. Akamai says Fast Purge processes updates in seconds.
Tiering and origin protection
Tiered Distribution has edge servers fetch from Akamai parent servers, which go to the origin only when necessary.
Edge compute
EdgeWorkers (JavaScript).

Strengths for caching

  • Invalidate-by-default purging by cache tag, so stale copies can be revalidated instead of refetched.
  • Prefresh: after 90% of the TTL by default, a request is served from cache and triggers an asynchronous revalidation.
  • Serve stale if unable to validate: a stale object is served when the origin can't be reached or returns a 5xx error.

Watch-outs

  • Cache state is only visible with Pragma debug headers, which you must send on purpose.
  • Origin Cache-Control and Expires are ignored until the Caching behavior is set to honor them.
  • Request collapsing is not described in the pages we reviewed.

Cache warming on Akamai

Akamai edge servers cache independently. With Tiered Distribution, a miss at the edge goes to a parent server first, so warming fills the parent tier that other edge servers fill from. See tiered caching.

Send the Pragma debug headers on warming requests so each response tells you what happened. TCP_MISS on the first request and TCP_HIT or TCP_MEM_HIT on the next one confirm the page is cached on that edge server.

curl -sI https://www.example.com/ \
  -H 'Pragma: akamai-x-cache-on, akamai-x-get-cache-key' | grep -iE '^x-cache'
# X-Cache: TCP_MISS from a23-0-0-1 (AkamaiGHost/...)

After a release, invalidate by cache tag rather than deleting: invalidated objects are revalidated with the origin using If-Modified-Since, and unchanged objects do not need a full download. Prefresh also keeps busy pages from going cold at TTL expiry. The Top 10 CDNs comparison shows how Akamai scored.

Frequently asked questions

How do I see whether Akamai served a page from cache?

Send Pragma: akamai-x-cache-on with the request. The response then includes X-Cache with a code such as TCP_HIT or TCP_MISS.

Should I use Invalidate or Delete in Fast Purge?

Akamai describes Invalidate as the default and most popular option: objects are revalidated with the origin on the next request, and a full download happens only when the content changed. Delete removes them outright, which can increase origin load and bandwidth.

Related terms

Akamai documentation

  1. Akamai: Pragma headershttps://techdocs.akamai.com/edge-diagnostics/docs/pragma-headers
  2. Akamai: Know your caching optionshttps://techdocs.akamai.com/property-mgr/docs/know-caching
  3. Akamai: Caching behaviorhttps://techdocs.akamai.com/property-mgr/docs/caching-2
  4. Akamai: Tiered Distributionhttps://techdocs.akamai.com/property-mgr/docs/tiered-dist
  5. Akamai: Purge methodshttps://techdocs.akamai.com/purge-cache/docs/purge-methods
  6. Akamai: Purge content by cache taghttps://techdocs.akamai.com/purge-cache/docs/purge-content-cache-tag
  7. Akamai: Assign cache tagshttps://techdocs.akamai.com/purge-cache/docs/assign-cache-tags
  8. Akamai: Fast Purgehttps://techdocs.akamai.com/purge-cache/docs/welcome-purge
  9. Akamai: EdgeWorkershttps://techdocs.akamai.com/edgeworkers/docs/welcome-to-edgeworkers

Warm your cache after every deploy

sitewarm requests the pages in your sitemap after a deploy and reports the cache state the CDN returns for each one, with the vantage point it was measured from.

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