Akamai Tools: Purge and CLI
Using the Akamai CLI to check a file, purge it, and check again. Invalidate versus delete, how to read x-cache, and why a purge reaches only the CDN layer.
I used the Akamai CLI to run one cycle: check the file, purge, then check again.
After a file changes, users still see the old version. The first thing most people think of is purge. I wanted to understand what a purge really does.
Two Kinds of Purge
| Invalidate | Delete | |
|---|---|---|
| Action | Mark the copy as expired | Remove the copy |
| Next request | Asks with the ETag, may get a 304 | Downloads the whole file again |
| Origin load | Low | High |
| Use | Normal updates | The old version must never appear again |
- We have several upload services. Only a few of them call purge. The others rely only on TTL expiry.
Common Commands
curl -sI "https://cdn.example.com/assets/{id}/{file}" # note the date and etag
akamai --section default purge invalidate --staging "<url>" # credentials in ~/.edgercAfter the purge, wait 5 seconds and run curl again (add Pragma: akamai-x-cache-on):
HTTP/2 200
etag: "32b7140e..."
-date: Sat, 18 Oct 2026 08:00:00 GMT
-x-cache: TCP_HIT from a23-...
+date: Sat, 18 Oct 2026 08:05:07 GMT
+x-cache: TCP_REFRESH_HIT from a23-...x-cachechanged fromTCP_HITtoTCP_REFRESH_HIT: the copy became expired, and the edge went back to the origin to ask.etagdid not change: the content is the same. The origin returned 304, and the edge kept the original copy (Cache Freshness: Fresh, Stale, and 304).
A purge reaches only the CDN layer. At that time I thought there was no other cache behind the origin. So I believed that after a CDN purge I would always get the new file. Later I found this belief was wrong (Two Cache Layers: What I Believed).
A purge clears the layer you can see. The layer you cannot see puts the old file back.
Sources: Akamai: EdgeGrid, Akamai: purge methods
Related: Cache Freshness: Fresh, Stale, and 304, Akamai Property: One Edge Config, Two Cache Layers: What I Believed. Or go back to the series overview.