HTTP 422 – Unprocessable Content
The request was well-formed but contains semantic errors, e.g. failed validation.
Common use case
Widely used by REST APIs (especially Rails and Laravel-style frameworks) to report field-level validation errors, e.g. an email address that isn't in a valid format.
Example
HTTP/1.1 422 Unprocessable Content
{"errors":{"email":["is invalid"]}}History
Originally defined for WebDAV in RFC 2518/4918 as "Unprocessable Entity"; renamed to "Unprocessable Content" in RFC 9110 (2022) and adopted well beyond WebDAV as the standard validation-error code.
Did you know?
It has become the de facto standard for form/API validation errors even though it started life as a niche WebDAV code.