Malformed request

Meaning

The request could not be parsed. Its body, path, or transport-level representation does not have the form required by the endpoint.

When it is returned

The API returns this problem for JSON syntax errors, unreadable request bodies, unsupported body representations, and path values that cannot be parsed into the required primitive type.

This differs from validation: a validation problem parsed successfully but failed a schema or business rule.

Client handling

Do not retry the same request. Correct its syntax, Content-Type, encoding, or path value before sending it again. Log the response detail for diagnosis, but do not use detail as a machine identifier.