Use decorators to validate forms

Flask-WTF-Decorators is easy to use. You can define a view that requires validation. from flask-wtf-decorators import FormValidator form_validator = FormValidator() @form_validator.validate_form(TestForm) @app.route('/', methods=['GET', 'POST']) def index(form): pass You can tell Flask-WTF-Decorators what to do when a form is illegal. To do this you should provide a callback for error_handler. @form_validator.error_handler def error_handler(errors): return jsonify({'errors': errors}), 400