HTTP 422 Unprocessable Content

What does HTTP 422 mean?

The request is well-formed but contains semantic errors. Popular in REST APIs (Rails, Laravel, FastAPI) for validation errors: the JSON is valid, but a required field is missing, an email is invalid or a value is out of range. The body should list the field errors.

4xx Client error: The request has a problem the client can fix: wrong URL, missing credentials, bad data or too many requests.

Common causes of a 422 error

• Validation failed for one or more fields.

How to fix 422 Unprocessable Content

• Read the error body and fix the listed fields.

422 and SEO

Not relevant for web pages.

Example response

HTTP/1.1 422 Unprocessable Content

How to return a 422 response

Node.js (Express)

res.status(422).json({ error: 'Unprocessable Content' });

PHP

http_response_code(422);

Python (Flask)

return {'error': 'Unprocessable Content'}, 422

Go (net/http)

w.WriteHeader(422)

nginx

return 422;

Related status codes

• 400 Bad Request — The server cannot process the request because it is malformed.
• 409 Conflict — The request conflicts with the current state of the resource.
• 415 Unsupported Media Type — The server does not support the format of the request body.

Check which status code a URL returns with the HTTP header checker.