HTML Form
Reference for building an HTML form that submits to formbuild.io: endpoint URL, encoding types, field names, honeypot, CORS, and a working example.
Use a standard HTML form and point it at your formbuild.io endpoint. No JavaScript or backend required on your side.
Endpoint
Your form must POST to:
https://formbuild.io/in/YOUR_FORM_ID```
Replace YOUR_FORM_ID with the ID shown on your
form's Integration tab in the dashboard.
Method and encoding
Set method="post". We accept three content types:
-
application/x-www-form-urlencoded — the default for HTML forms. Use this for simple text fields.
-
multipart/form-data — alternative encoding. Set
enctype="multipart/form-data"on the form tag. -
application/json — send a JSON object via
fetch()or from an SPA. Each key is a field name and each value is stored as a string. See API Submissions.
Field names
Every input, textarea, or
select with a name attribute is sent and
stored. The name becomes the label shown in your Inbox
(e.g. email, message, phone).
You can use any names you like.
Special names: if your form includes a field named
email, _replyto, or replyto, we
automatically validate it as an email address. A non-empty value that
isn't a valid email will be rejected.
Cross-origin (CORS)
The submission endpoint allows requests from any origin. We respond to
OPTIONS preflight with 204 and
Access-Control-Allow-Origin: *, so you can embed forms on
other domains or submit via fetch() from a different site.
Honeypot field (optional)
In your form settings under Spam, you can set a
honeypot field name. Add a hidden input with that name to
your form. If a bot fills it in, we silently discard the response
(returning a success status so the bot doesn't retry). See
Spam protection.
Preview
You can preview and test your form from the dashboard. Open the form, go to the Integration section, and click Preview form. You'll see the form as visitors see it and can submit a test — it shows up in your Inbox like a real response.