Documentation / Fastly Features / Pragma X-TB Headers

Pragma X-TB Headers

Returns a response carrying three custom headers prefixed with x-tb-, for testing custom header handling and header forwarding through a delivery chain.

Endpoint

GET/fastly_features/x-tb-headers

No parameters. Every request returns the same three headers, which makes it a stable reference point when you are checking what survives a proxy, a cache, or a client.

Headers returned

Header Value
x-tb-header1 value1
x-tb-header2 value2
x-tb-header3 value3

Usage example

curl -i https://your-service.edgecompute.app/fastly_features/x-tb-headers

Browsers hide most response headers, so use curl -i or curl -D - to see the full set.

Expected response

HTTP/1.1 200 OK
Cache-Control: private, no-store
x-tb-header1: value1
x-tb-header2: value2
x-tb-header3: value3

Nice x-tbs!

Notes

If fewer than three x-tb- headers reach your client, something between the edge and the client stripped them. Comparing this response at the edge against what arrives downstream is the point of the test.

  • The response is sent with Cache-Control: private, no-store, so each request is served fresh.
  • Header names are case-insensitive, but some tooling normalizes them to lowercase on display.

Ready to test?

Fetch the endpoint and check which headers make it through to your client.

Try it now