# 203 Non-Authoritative Information > https://http-status.org/docs/203 **Family:** 2xx Success ## Rationale The request succeeded, but the returned representation was modified by a transforming proxy. ## In Plain Terms The request worked, but the response may have been adjusted by something in the middle, like a proxy, before it reached you. ## Description The HTTP 203 Non-Authoritative Information status code indicates that the request succeeded, but the enclosed representation was modified from the origin server's 200 OK response by a transforming proxy. ## Server Perspective ### Usage - Return 203 when an intermediary rewrites, adapts, or transforms the representation - Use it to help clients understand that the payload is derived from a 200 response but not identical to it - Transforming proxies that rewrite or optimize the origin response - Intermediaries that adapt content and want to be explicit that the payload is not byte-for-byte authoritative - Systems where the client should know a middle layer changed the original representation ### Implementation - Preserve normal response metadata where possible and document proxy transformations clearly - Use 200 instead when the origin server itself is intentionally returning that representation ### Common Headers - No status-specific header is required; preserve or document metadata affected by the intermediary transformation. ### Body - Return the transformed representation in the response body ### Pitfalls - Do not use 203 for ordinary application responses from the origin server - Do not hide important data loss or semantic changes without making the transformation clear - Origin servers returning their own authoritative representation - Unmodified successful responses that should simply be 200 OK - Application-level data shaping performed by the origin service itself ## Client Perspective ### Pitfalls - Do not assume a 203 payload is byte-identical to the origin server's response ## Examples ### Proxy-compressed HTML response with transformations A transforming intermediary changed the origin's response and signals that the payload is not exactly what the origin sent. **Request:** ``` GET https://api.example.test/news ``` **Response:** ``` 203 Non-Authoritative Information Content-Type: text/html; charset=utf-8 Transformed content ``` ## Related Codes - [200 OK](/docs/200.md) - [204 No Content](/docs/204.md) - [304 Not Modified](/docs/304.md)