HTTP headers
ETag HTTP Header Meaning
ETag identifies a specific version of a resource representation.
Meaning
The server is giving the response body a validator that clients can use later.
Where it appears
Servers send it on cacheable responses; clients reuse it in conditional requests.
What to check
Check whether the ETag changes when content changes and whether weak or strong validation is intended.
Example
ETag: "33a64df551"References
- Registry
- IANA HTTP Field Name Registry
- Guide
- MDN ETag