Form JSON validator

Updated 2026-11-01

Paste your form definition as JSON. The checker shows which fields are valid and which are not. Each problem has a plain reason. It uses the same form check as the AI Form API. You see what the API would say. Nothing leaves your browser.

Check your form

Paste the JSON you send to the API, or the JSON from a template page.

Nothing leaves your browser. The check runs on this page.

What the checker looks at

  • The form has a title.
  • The form has 1 to 50 fields.
  • Each field has an id, a label and a type.
  • Ids are snake_case and are not repeated.
  • Choice fields have at least 2 different options.
  • Options like min, max and max_length fit the field type.
  • No field asks for a password, a card number or an ID number.

How to use it

  1. Paste the JSON in the box. You can copy it from a template page or from your own code.
  2. Press Check the form.
  3. Read the list of fields. Each one says Valid or Problem.
  4. Fix the problems in your JSON and check again.

Problems you may see

  • The id has capital letters or spaces. Use first_name, not First Name.
  • A choice field has no options. Add at least 2 options.
  • Two fields share an id. Give each field its own id.
  • A label asks for a password. Remove the field. The API blocks it.
  • A field has an unknown property. Remove it or fix the spelling.

Next steps

When the form passes, send it to the Forms API. The quickstart shows the first call. See forms and fields for every field type. Or start from a template.

Questions

Does my JSON leave my browser?

No. The check runs on this page. It does not send your text to a server.

Which rules does it use?

The same rules as the AI Form API. The API can still say no for other reasons, such as plan limits.

Why is my field id not valid?

An id uses lower-case letters, digits and underscores. It starts with a letter. It has at most 40 characters.

How many fields can a form have?

A form has 1 to 50 fields.

Which field types can I use?

short_text, long_text, email, number, url, phone, single_choice, multi_choice, checkbox, date and rating.

Why was my field blocked?

A form cannot ask for secrets. That means passwords, codes, card or account numbers, and passport or ID numbers. This stops phishing.

Can I paste JSON from an AI chat?

Yes. A fence of three backticks around the JSON is fine. The checker ignores it.

Does it check answers too?

No. It checks the form definition only. It does not read any answers.

Why do new problems show up after I fix one?

Some checks run only when the shape of the form is right. Check again after each fix.

Does it cost anything?

No. You need no account and no key.