Submission API Reference & Form Configuration

Submit a Form

Send data to a form endpoint. This is identical to a standard HTML form POST.

POST https://formboost.app/f/:endpoint_id

JSON submission

const response = await fetch("https://formboost.app/f/YOUR_ENDPOINT_ID", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    email: "user@example.com",
    message: "Hello from the API"
  })
});

if (!response.ok) {
  const error = await response.json(); // { success, message, name, hint }
}

cURL example

curl -X POST https://formboost.app/f/YOUR_ENDPOINT_ID \
  -H "Content-Type: application/json" \
  -d '{"email": "user@example.com", "message": "Hello"}'

Response

The endpoint accepts the submission and processes it in the background, so the answer is immediate. What you get depends on how you sent it:

• JSON or fetch() clients (Accept: application/json, or a JSON body) receive 202 Accepted:

{
  "success": true,
  "message": "Submission accepted for processing",
  "requestId": "3f1c…"
}

• Plain HTML form posts receive a 302 redirect — to your _redirect URL when it is an https URL on the same host as the submitting page, otherwise to the default thank-you page.

requestId is the identifier of this request, useful when reporting a problem. It is not a lookup key: submissions are read in the dashboard, not through this endpoint. Check response.ok rather than parsing the body for success.

Error Codes

Errors are JSON with success: false, a human message, and a machine-readable name to branch on, plus a hint saying what to change:

Required fields are not validated at the endpoint — every non-empty submission is accepted. An unknown endpoint id is also accepted and discarded during processing, so check the id in the dashboard rather than relying on a 404. A plain HTML form post never sees JSON: on an error it is redirected to the default page instead.

Special Fields

These hidden fields control Formboost behavior without being stored as submission data:

Email Notifications

By default, Formboost sends an email notification to your account email for every submission. You can customize this under Endpoint → Notifications.

These emails go to you. To email the person who filled in the form instead, see Auto Reply. It is available on Starter and above, with HTML templates and {{fieldName}} variables on Pro.

Spam Protection

Formboost uses AI-powered spam filtering. Configure sensitivity under Endpoint → Spam Protection.

Honeypot Fields

Add a hidden input that humans never fill in. Bots usually do.

<form action="https://formboost.app/f/YOUR_ENDPOINT_ID" method="POST">
  <!-- Honeypot: hidden from real users -->
  <input type="text" name="_honey" style="display:none" tabindex="-1" autocomplete="off" />

  <input type="email" name="email" required />
  <button type="submit">Submit</button>
</form>

Set _honey as the honeypot field name in your endpoint settings to activate detection.