422 Unprocessable Entity

The syntax is valid but the content fails the server's validation rules.

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Status code422
Status textUnprocessable Entity
Category4xx Client Error
Response has bodyUsually
SpecificationRFC 9110

What does 422 Unprocessable Entity mean?

The syntax is valid but the content fails the server's validation rules. It belongs to the 4xx Client Error class, which means the request contains bad syntax or cannot be fulfilled. Something about the request needs to change.

When do APIs return 422?

Well-formed JSON that breaks a business rule — an invalid email, a date in the past, a value out of range.

How to fix a 422 Unprocessable Entity

Distinct from 400: your JSON parsed fine, but the data is not acceptable. Read the response body, which usually lists the failing fields, and correct the values.

Reproduce a 422 response

The fastest way to understand a status code is to trigger one and read the full response. Open the API tester and send a request to https://httpbin.org/status/422 — you will see the 422 status along with every response header the server sent. Comparing those headers against a working request is often what reveals the cause.

When you are debugging a real endpoint, check the response headers as carefully as the body, and confirm you are using the right HTTP method for the operation.

Related 4xx status codes

400 Bad Request

The server could not understand the request because it is malformed.

401 Unauthorized

The request lacks valid authentication credentials. Despite the name, this means unauthenticated.

402 Payment Required

The request cannot be processed until payment is made.

403 Forbidden

The server understood the request and knows who you are, but refuses to authorise it.

404 Not Found

The server cannot find the requested resource.

405 Method Not Allowed

The endpoint exists but does not support the HTTP method you used.

422 Unprocessable Entity FAQ

When should I use 422 instead of 400?

Use 422 when the request is syntactically fine, for example valid JSON, but the values break a rule: a required field is missing, an email is malformed, a date is in the past. Use 400 when the request cannot be parsed at all.

What does a 422 response body usually contain?

A list of the fields that failed validation and why. The exact shape differs by API, so read the body rather than relying on the status code alone.

Is 422 a client error or a server error?

A client error. The server is working and understood the request; the data sent needs to change before the request can succeed.

See also

  • 400 Bad Request — The server could not understand the request because it is malformed.
  • 409 Conflict — The request conflicts with the current state of the resource.

References