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Run a contact form on Netlify that keeps working if you move host

To use FormThunder on a Netlify site, write a normal form and leave out the data-netlify attribute, so Netlify's build ignores it and the post goes straight to FormThunder. Netlify's built-in Forms are a good choice if you'll stay on Netlify. FormThunder suits sites that may move hosts, or that need signed webhooks or branded emails.

Updated

The Netlify code

contact.html
<form action="https://formthunder.com/submit" method="POST">
  <input type="hidden" name="access_key" value="YOUR_ACCESS_KEY">
  <input type="hidden" name="subject" value="New message from the website">
  <input type="checkbox" name="botcheck" style="display:none" tabindex="-1" autocomplete="off">

  <label for="name">Name</label>
  <input id="name" name="name" required>

  <label for="email">Email</label>
  <input id="email" name="email" type="email" required>

  <label for="message">Message</label>
  <textarea id="message" name="message" rows="5" required></textarea>

  <button type="submit">Send</button>
</form>
netlify.toml
[context.production.environment]
  FORMTHUNDER_KEY = "YOUR_PRODUCTION_KEY"

[context.deploy-preview.environment]
  FORMTHUNDER_KEY = "YOUR_PREVIEW_KEY"

Replace YOUR_ACCESS_KEY with your free key. It's public by design, so it's safe in client code.

Notes for Netlify

  • Netlify's form detection only touches forms marked data-netlify="true" or netlify. A leftover attribute means Netlify rewrites the form at deploy time, so remove it when you switch.
  • Remove the hidden form-name field too, if you added it for JavaScript-rendered forms.
  • If your build tool needs the key in client code, use its public prefix in netlify.toml, such as VITE_FORMTHUNDER_KEY.
  • Deploy previews use deploy-preview-N--yoursite.netlify.app hosts. Keep a preview key without domain restriction so previews can send.

Or have your AI add it

Connect the MCP server, then ask. The agent creates the form and writes the code for you, and it can send a real test when it's done.

You, to your AI
Add a FormThunder contact form to this Netlify site that emails hello@example.com. Send a test when you're done.

Questions

Should I just use Netlify Forms?

If your site will stay on Netlify and you don't need more than it offers, it's a fine choice. Our comparison page sets out the differences.

Can both run on one site?

Yes. Forms marked data-netlify go to Netlify, and the others post wherever their action says.

Related guides

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