Non-Authoritative Information

Server perspective

Use 203 mainly from a transforming proxy when the origin's successful response was modified before delivery.

When to use

• •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

How to respond

• •Preserve normal response metadata where possible and document proxy transformations clearly
• •Use 200 instead when the origin server itself is intentionally returning that representation

Headers to consider

• •No status-specific header is required; preserve or document metadata affected by the intermediary transformation.

Response body

• •Return the transformed representation in the response body

Server-side 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

Examples