HTTP 422 — Unprocessable Content
HTTP 422
Unprocessable Content
The request is well-formed and understood, but the data in it fails the rules.
What 422 actually means
The syntax is fine — the JSON parsed, the fields are the right types — but the content does not make sense to the application. An end date before a start date, an email address that is not an address, a quantity of −3. This is the precise code for validation failures, where 400 says only "I could not parse this". It originated in WebDAV but is now the convention across most modern APIs.
Common causes
- Field-level validation failed on otherwise valid JSON
- A required business rule violated, such as an end date before a start date
- A referenced ID that does not exist
- A value outside an allowed range or enumeration
- Semantic errors in a WebDAV XML request body
If you're just trying to view the page
- Check the form for a field-level error message — the site usually highlights what was wrong
- Look for values that are individually plausible but inconsistent, like dates in the wrong order
- Re-enter data that was pasted; invisible characters from other applications often cause this
If it's your site
- Return a structured list of which fields failed and why; a bare 422 is barely better than a 400
- Use 422 for validation and keep 400 for genuinely unparseable requests — the distinction is the point
- Do not use 422 for authorisation problems; that is 403
- Make sure your validation errors are stable enough for clients to map to their own UI strings
Reference
- Status code
- 422
- Reason phrase
- Unprocessable Content
- Category
- 4xx — Client Error
- Defined in
- RFC 9110 §15.5.21
Common questions
- What does HTTP 422 mean?
- The request is well-formed and understood, but the data in it fails the rules. The syntax is fine — the JSON parsed, the fields are the right types — but the content does not make sense to the application. An end date before a start date, an email address that is not an address, a quantity of −3.
- How do I fix a 422 error?
- Check the form for a field-level error message — the site usually highlights what was wrong
- Is 422 a client error or a server error?
- 422 is in the 4xx range, which means client error. The request itself was the problem, so retrying it unchanged will usually return the same code.
Related pages
- 404 Not Found The server is reachable and working, but there is nothing at the address you ask
- 403 Forbidden The server understood the request and is refusing to allow it, and logging in wi
- 401 Unauthorized You need to authenticate, and either you did not or your credentials were reject
- 429 Too Many Requests You have sent more requests than the service allows in a given period.
- 400 Bad Request The server could not understand the request because something about it is malfor
- 413 Content Too Large The request body is bigger than the server is willing to accept.
- 405 Method Not Allowed The URL exists, but it does not accept the HTTP method you used.
- 409 Conflict The request cannot be completed because it clashes with the current state of the
- 415 Unsupported Media Type The server will not accept the format of the body you sent.
- 408 Request Timeout The server gave up waiting for the client to finish sending its request.
- 410 Gone The resource was deliberately removed and is not coming back, and there is no fo
- 451 Unavailable For Legal Reasons The content is blocked because of a legal demand — a court order, takedown notic