Your Form Endpoint

Every Formbase form is identified by a unique ID. Your submit endpoint is always the base URL of your Formbase instance plus /s/<form-id>. For the hosted service:

https://formbase.dev/s/YOUR_FORM_ID

For self-hosting:

https://your-domain.com/s/YOUR_FORM_ID

What the endpoint accepts

Formbase accepts the formats that browsers and APIs commonly send:

multipart/form-data (for file uploads)
application/x-www-form-urlencoded (standard HTML forms)
application/json (server submissions and API-style posts)

The same /s/<form-id> path is used for both POST submissions and the built-in success page. Browser posts return a 303 redirect to that page.

Example submissions

HTML
Server JSON

index.html

<form action="https://formbase.dev/s/YOUR_FORM_ID" method="POST">
  <input name="name" placeholder="Name" required />
  <input name="email" type="email" placeholder="Email" required />
  <button type="submit">Send</button>
</form>

Use enctype="multipart/form-data" when uploading files.

const response = await fetch('https://formbase.dev/s/YOUR_FORM_ID', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ plan: 'pro', userId: '123' }),
});

const result = await response.json();
console.log(result.data);

This is the best approach when you need a JSON response.

CORS and preflight

Formbase responds to OPTIONS preflight requests on /s/<form-id> and allows cross-origin POSTs by default. This makes it easy to post from any frontend.

Receive a Submission HTML Forms

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Getting Started

Integrations

File Uploads

Form Settings

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Submissions

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FAQ

Your Form Endpoint

What the endpoint accepts

Example submissions

CORS and preflight

​What the endpoint accepts

​Example submissions

​CORS and preflight

What the endpoint accepts

Example submissions

CORS and preflight