// http 4xx · client error
HTTP 422 Unprocessable Entity
Well-formed but semantically invalid (validation failed).
What HTTP 422 Unprocessable Entity means
422 Unprocessable Entity means the request was well-formed (valid syntax) but failed semantic validation — the values don't make sense or violate business rules. It's the go-to code for form and API validation errors.
Which category is it?
422 is a 4xx code — Client error. 4xx means the request has a problem the client must fix — bad syntax, missing authentication, or a resource that isn't there. It's the caller's responsibility.
Common causes
- Field validation failed (required, format, range)
- Business-rule violations the syntax can't catch
- References to records that don't exist
How to fix it
- Fix the specific fields named in the error response
- Validate input client-side before sending
- Read the API's validation error details