Updated March 2026
An HTTP endpoint that accepts form data as a POST request. It handles validation, storage, and delivery so you don't build your own backend for this.
Sutrena's submission endpoint is POST /api/forms/{id}/submit. It's public -- no auth required. This is intentional. The endpoint gets called from users' browsers, and you should never put API keys in frontend code. The form ID in the URL identifies which form the data belongs to.
What happens when a submission arrives? Validation first. Required fields must be present. Email fields must look like emails. Select fields must match predefined options. Numbers must be in range. Fail? 400 error with details about which fields are wrong.
After validation, storage. Timestamped in the database. If the form has linked webhooks, Sutrena fires a POST to each webhook URL with the submission data as JSON, signed with HMAC-SHA256 if a secret is configured. If maxSubmissions is set and reached, the submission is rejected with 429.
The endpoint accepts application/json. For file uploads, it handles multipart/form-data too.
For traditional HTML forms without JavaScript, set the form's action attribute to the endpoint and use method="POST". It accepts URL-encoded data as well. After submission, it redirects to the form's successRedirect or returns JSON.
This endpoint is the core of the headless form backend. Use it from any frontend framework, mobile app, server-side script, or API client. Submissions are queryable through GET /api/forms/{id}/submissions (which does require auth), and they feed dashboards and CSV exports.
# Submit data to a form (no auth required)
curl -X POST https://sutrena.com/api/forms/FORM_ID/submit \
-H "Content-Type: application/json" \
-d '{
"email": "[email protected]",
"message": "Hello from the API"
}'