form-backend / live example

posting to —

Original

Fill this in.

An ordinary HTML form, posted to a backend on a different origin. Nothing here is special — that is the point.

What is this about?

Adding a file switches the request to multipart/form-data.

Carbon copy — what the server receives

POST /f/…
content-type: application/json

name
email
topics
message
attachment

Response

Not sent yet.
    The markup that did this

    This page uses fetch so it can show you the response. It does not have to — the same form works with no JavaScript at all. Set action to your endpoint and the backend redirects to your thank-you page on success: 

    <form action="https://api.example.com/f/YOUR_FORM_ID" method="POST"
      enctype="multipart/form-data">
  <input name="name" required>
  <input name="email" type="email" required>
  <input name="topics" type="checkbox" value="sales">
  <input name="topics" type="checkbox" value="support">
  <textarea name="message"></textarea>
  <input name="attachment" type="file">

  <!-- bots fill this in; people never see it -->
  <input name="_gotcha" style="display:none" tabindex="-1" autocomplete="off">

  <button>Send it</button>
</form>

    Send content-type: application/json and you get JSON back ({"ok":true,"id":"…"}). Post it as a form and you get a 302 to your redirectUrl, or to the hosted thank-you page if you have not set one.