HTTP 203 Non-Authoritative Information
Updated Free mock REST & WebSocket APIs
HTTP 203 Non-Authoritative Information — The request succeeded but a transforming proxy modified the origin's response.
- Class
- 2xx Success
- Defined in
- RFC 9110 §15.3.4
- Official
- Yes (IANA registry)
- Cacheable by default
- Yes (heuristically, per RFC 9110)
Try it: get a real 203 response
Our test endpoint answers every request with 203 Non-Authoritative Information.
curl -i https://mockfox.dev/api/status/203Use it in tests, health-check monitors or to see how your client handles a 203. Add ?delay=2000 to slow it down.
What does HTTP 203 mean?
A proxy that changes the payload (for example recompressing images or stripping content) may replace a 200 with 203 to signal that the content isn't exactly what the origin sent. It's rare in practice; most proxies leave the status untouched.
Handling 203
- Visitors: Nothing to fix — this is a success status.
- Developers: Make sure clients handle this status as success (
response.okis true for 200–299) and know whether to expect a body.
Example 203 response
HTTP/1.1 203 Non-Authoritative Information
Content-Type: application/json
{"status":203,"error":"Non-Authoritative Information"}2xx Success: The request was received, understood and accepted. See the full list of HTTP status codes.
Related status codes
- 200 OKThe request succeeded and the response contains the result.
- 304 Not ModifiedThe cached copy the client already has is still valid, so no body is sent.
Related tools
Frequently asked questions
What does HTTP 203 Non-Authoritative Information mean?
The request succeeded but a transforming proxy modified the origin's response.
Is 203 an error?
No. 203 is a success status.
Where is 203 defined?
In RFC 9110 §15.3.4. It's listed in the IANA HTTP Status Code Registry.
How can I test how my app handles a 203?
Call https://mockfox.dev/api/status/203 — it responds with 203 to any method, with CORS enabled. Add ?delay=2000 to simulate a slow response.