---
set: 2
code: 203
title: Non-authoritative Information
references:
    "Rails HTTP Status Symbol": ":non_authoritative_information"
    "Go HTTP Status Constant": "http.StatusNonAuthoritativeInfo"
---

The request was successful but the enclosed payload has been modified from that
of the origin server's [200 OK](/200) response by a transforming
proxy<sup>[1](#ref-1)</sup>.

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<sup>[2](#ref-2)</sup>, which has the advantage of being applicable to
responses with any status code.

A 203 response is cacheable by default; i.e., unless otherwise indicated by the
method definition or explicit cache controls<sup>[3](#ref-3)</sup>.

---

* <span id="ref-1"><sup>1</sup> Transformations
[RFC7230 Section 5.7.2][2]</span>
* <span id="ref-2"><sup>2</sup> Warning [RFC7234 Section 5.5][3]</span>
* <span id="ref-3"><sup>3</sup> Calculating Heuristic Freshness
[RFC7234 Section 4.2.2][4]</span>
* Source: [RFC7231 Section 6.3.4][1]

[1]: <http://tools.ietf.org/html/rfc7231#section-6.3.4>
[2]: <http://tools.ietf.org/html/rfc7230#section-5.7.2>
[3]: <http://tools.ietf.org/html/rfc7234#section-5.5>
[4]: <http://tools.ietf.org/html/rfc7234#section-4.2.2>