Migrate from Web3Forms to FormThunder by changing the URL and the key
To migrate from Web3Forms to FormThunder, change the form's action URL to the FormThunder submit URL and swap the access key. You don't have to change your field names, because FormThunder accepts the same ones. Your redirects, honeypot and subject lines keep working. It's a two-line change per form, and an AI agent can do it across a whole site.
The change
- <form action="https://api.web3forms.com/submit" method="POST">
- <input type="hidden" name="access_key" value="YOUR_WEB3FORMS_KEY">
+ <form action="https://formthunder.com/submit" method="POST">
+ <input type="hidden" name="access_key" value="YOUR_FORMTHUNDER_KEY">If you submit with fetch, change the URL you post to. The rest of your code stays.
Step by step
- Get a key and verify the address that should receive submissions.
- Change the action URL and the access key in one form.
- If the form uses hCaptcha, Turnstile or uploads, replace the Web3Forms script with ours and turn on the matching setting.
- Send a real test from the page, and check your inbox and the dashboard.
- Repeat for your other forms, and then leave the old account until you're sure nothing still posts to it.
Field by field
| Web3Forms field | On FormThunder |
|---|---|
| access_key | Same name. Use your new key. |
| subject, from_name, replyto | Work as they are. |
| redirect | Works as it is. It must be an absolute URL. |
| botcheck | Works as it is: the honeypot. |
| ccemail | Works on Pro. CC addresses have to be verified linked emails. |
| webhook | Works on Pro, and must be HTTPS. |
| attachment | Works on Pro, with attachments turned on for the form. |
| h-captcha-response | Works. Turn hCaptcha on for the form, and use our script. |
| cf-turnstile-response, g-recaptcha-response, recaptcha_response | Work on Pro, with your own keys stored on the form. |
| Any other field | Forwarded as-is. Its name is its label in the email. |
Or have your AI do the whole site
Connect the MCP server, then ask. The agent can find each form, create a matching one and test it.
Move this site's forms off Web3Forms and onto FormThunder. Keep the field names, send to hello@example.com, and test each one.Questions
Do I have to change my field names?
No. FormThunder accepts the same reserved field names as Web3Forms, and forwards the rest as they are.
Does the JSON response stay the same?
It has success, message and body fields in the same shape, so code that checks success keeps working. It also has a submission_id.
Will my Web3Forms key work?
No. You need a key from FormThunder. Web3Forms and FormThunder are separate services.
Can I test before switching the live site?
Yes. Post from a staging page first, or run test_form, and check that the email arrives before you change production.
Is hCaptcha set up the same way?
Add a div with the h-captcha class and data-captcha="true", and load our /client/script.js in place of the Web3Forms one. Then set the form's captcha to hcaptcha.
Move one form and see how it goes
The free plan covers 250 submissions a month, with MCP, the CLI and the brand kit included.