AJAX submissions

By default, Formward responds to a form POST with a 302 redirect (the standard browser behaviour). For single-page apps or custom UIs where you want to stay on the page and handle the response yourself, send the request with an Accept: application/json header (or an X-Requested-With header) and Formward returns 200 { ok: true, id } instead.

Detection

Formward detects an AJAX request by inspecting the incoming headers. Either of these triggers JSON mode:

• Accept header contains application/json
• X-Requested-With header is present (any value)

fetch() example

async function submitForm(form) {
  const data = new FormData(form);

  const res = await fetch("https://forms.formward.eu/f/<formId>", {
    method: "POST",
    headers: {
      Accept: "application/json",
    },
    body: new URLSearchParams(data),
  });

  if (!res.ok) {
    const body = await res.json().catch(() => ({}));
    // See status codes in Responses & redirects
    throw new Error(body.error ?? `HTTP ${res.status}`);
  }

  const { ok, id } = await res.json();
  // ok: true, id: "<submissionId>"
  console.log("Submission recorded:", id);
}

Successful response

HTTP/1.1 200 OK
Content-Type: application/json

{ "ok": true, "id": "clxyz123..." }

The id is the submission ID assigned by Formward. You can use it to cross-reference entries in the dashboard.

Error responses

Error responses are also JSON when the request was sent in AJAX mode. The body shape is { ok: false, error: string }, with an additional upgrade: true field on plan-limit errors. See Responses & redirects for the full status code table.

Sending JSON vs form-encoded

The ingestion server accepts application/x-www-form-urlencoded bodies (standard form POST). When submitting via fetch pass new URLSearchParams(data) as the body. This produces a form-encoded body without needing to set a Content-Type header manually.

CORS

Cross-origin requests are gated by the allowed origins list on your form. If the Origin header of the request is not on that list (and the list is non-empty), the server returns 403. Add your site's origin in the form settings before going live.