Errors

All exceptions live in pydantic_forms.exceptions and subclass FormException.

Exception	Raised when	FastAPI status code
FormNotCompleteError	The wizard has more pages left; carries the next page’s JSON schema (.form) and, if the page defines any, its page metadata (.meta, otherwise None).	510 Not Extended
FormValidationError	Submitted input failed Pydantic validation; carries the translated errors (.errors).	400 Bad Request
FormOverflowError	More inputs were submitted than the wizard has pages for.	500 Internal Server Error
FormNotFoundError	start_form was called with a key that no form is registered under.	404 Not Found

FastAPI response shapes

The form_error_handler (see FastAPI integration) turns these into JSON responses with the status codes listed above. Any other FormException results in a 500 Internal Server Error.

Set the LOG_LEVEL_PYDANTIC_FORMS=DEBUG environment variable to include a traceback field in the 400 and 510 responses and in the logs.