HTTP 422 Unprocessable Content

Client error code, RFC 9110, section 15.5.21

What it means

The server understands the format of the request and the syntax is right, but the content cannot be processed, for example a form with values that make no sense.

A real response

This is the request and the answer our test server gave when we asked it to return 422.

GET /c/422 HTTP/1.1
Host: example.com

HTTP/1.1 422 Unprocessable Content
Date: Sat, 14 Nov 2026 10:00:00 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 11

<p>demo</p>

If you run the site

Common for validation errors in APIs: the JSON is valid (so not 400) but a field fails a rule, such as an email that is not an email. Return the list of fields and problems in the body.

If you are a visitor

Check what you typed in the form and fix the fields the message points to.

A common mistake

Using 422 for broken JSON, which is a plain 400.

Registered in the IANA HTTP Status Code Registry as Unprocessable Content, defined in RFC 9110, section 15.5.21.

This is an independent guide. It is not connected with the IETF, IANA, any browser maker or any company named here. Meanings were checked against the RFC texts on 14 November 2026. Responses shown were recorded on 14 November 2026 from a small test server on the author's own computer.