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
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
<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>
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);
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. 
