Send form submissions to email, webhooks and chat from one form backend
FormThunder receives posts from any HTML form, saves them and delivers them to your inbox, a webhook, Slack, Discord, Telegram or Google Sheets. Your AI can configure all of it over MCP or the CLI. It includes spam protection, file uploads, brand-matched email templates, a delivery log with retries, and client accounts for agencies.
Updated
The whole thing starts with one form tag.
contact.html
<form action="https://formthunder.com/submit" method="POST">
<input type="hidden" name="access_key" value="YOUR_ACCESS_KEY">
<input name="email" type="email" required>
<textarea name="message" required></textarea>
<button type="submit">Send</button>
</form>Set up by your AI
MCP server
48 tools for Claude Code, Cursor and any MCP client. On every plan.See the tools
CLI
npx formthunder does what the dashboard does, and every command takes --json.CLI reference
Errors with a next step
Each error has a hint that tells the agent what to do, and a link to the docs.
A live page check
check_form_on_site fetches your deployed page and returns a fix for anything that's wrong.
Form to email
Works with plain HTML
Post JSON, URL-encoded or multipart to one URL. CORS is open.Submit API
Your subject and sender
Set the subject, from name, reply-to and redirect, per form or per post.Customise a form
Verified recipients
Mail only goes to addresses you've verified, which is what makes a public key safe. 1, 5 or 10 per form by plan.
CC and autoresponder
On Pro. Autoresponses have per-address caps and need allowed domains.Autoresponder
Emails in your brand
Brand kit
Logo, colours, fonts, radius and footer, read from your site or set by hand. On every plan.
Built-in themes
Clean, Card and Letter on Free. Bold and Compact on Pro.
Custom HTML templates
Mustache variables, a preview that returns warnings, and test sends. On Pro.Email templates
AI-written templates
generate_template writes one from your brand kit and an optional URL.
Spam protection
Honeypot and content filter
On every plan. Flagged submissions go to a spam folder you can restore from.Spam protection
hCaptcha
On every plan, with a key we provide.
Turnstile and reCAPTCHA v3
On Pro, with your own keys stored on the form.
Domain restriction
On Pro. Accept posts only from your own sites.
Deliveries and integrations
Signed webhooks
HMAC-SHA256 on each post, with retries for up to 24 hours. On Pro.Webhooks
Chat and Sheets
Slack, Discord, Telegram and Google Sheets. On Pro.Integrations
Automation tools
Zapier, Make and n8n, through webhooks.
A delivery log
Status, attempts and last error for every delivery, with resend. On every plan.Reliability
Data and files
Dashboard history
30 days on Free, 1 year on Pro and Agency.
CSV export
On every plan.
File uploads
Direct up to 5 MB per file, or up to 25 MB through the advanced uploader. On Pro.Attachments
REST API
Forms, templates, clients and keys on every plan. The Submissions API is on Pro.API reference
Teams and agencies
Seats
1 on Free, 3 on Pro and 10 on Agency.
Audit log
What changed, and which person or key changed it. Handy after an AI session.
Client accounts
Unlimited and free on Agency. Upgrade any client for $5 a month.Agency accounts
Client billing
Charge clients a retainer through your own Stripe account.
Get a key and send your first test in a few minutes
The free plan covers 250 submissions a month, with MCP, the CLI and the brand kit included.