X-Cache
Response headers
Says whether a CDN answered from cache; HIT means the origin was never reached.
| On the wire | X-Cache: … |
|---|---|
| Category | Response headers |
Headers the server attaches when it answers.
How to read this
- The first digit of a status code carries the meaning: 4 means the request, 5 means the server.
- 404 means "not there"; 403 means "there, but not for you". Swapping them makes debugging slower.
- Header names are case-insensitive — Content-Type and content-type are the same header.
- Caching and CORS problems usually come down to one header line, visible in the browser’s network tab.
Frequently asked questions
Q. What does HTTP X-Cache mean?
Says whether a CDN answered from cache; HIT means the origin was never reached.
Q. What does X-Cache look like on the wire?
It travels as X-Cache: …
Q. Where does X-Cache appear?
In response headers.
Q. What group does X-Cache belong to?
The response headers group; the rest of that group is listed further down.