203 Non-authoritative Information - Success Response Status Code

Example Use

The request was a successful 200 (OK) response but it was modified by a proxy server before delivering the final result.

A popular scenario is placing a proxy server in front of a web server to cache and/or transform content to reduce load on the web server.

Official Definition

The request was successful but the enclosed payload has been modified from that of the origin server's 200 (OK) response by a transforming proxy. This status code allows the proxy to notify recipients when a transformation has been applied, since that knowledge might impact later decisions regarding the content. For example, future cache validation requests for the content might only be applicable along the same request path (through the same proxies).

The 203 response is similar to the Warning code of 214 Transformation Applied, which has the advantage of being applicable to responses with any status code.

A 200 response is cacheable by default unless otherwise indicated by the method definition or explicit cache controls.

Source: RFC 7231 Section 6.3.4