1. Sign up and create a form

Sign in with a magic link. From the dashboard, click New form, give it a name like contact, and copy the endpoint URL.

2. Drop the endpoint into your HTML

Replace YOUR-FORM-ID with the ID from the dashboard. Any field names you use here will appear in the destination delivery.

<form
  action="https://routepost.dev/api/f/YOUR-FORM-ID"
  method="POST"
>
  <input name="name"    placeholder="Your name"    required />
  <input name="email"   placeholder="you@example.com" type="email" required />
  <textarea name="message" placeholder="What's up?" required></textarea>

  <!-- Honeypot — must stay empty. Bots fill it; humans don't. -->
  <input type="text" name="website" style="display:none" tabindex="-1" autocomplete="off" />

  <button type="submit">Send</button>
</form>

3. Add a destination

Open your form in the dashboard, scroll to Destinations, and add at least one. Email + Slack + webhook can all coexist — every destination receives every submission in parallel.

4. Test it

Send a request from the terminal to verify everything before publishing the form:

curl -X POST https://routepost.dev/api/f/YOUR-FORM-ID \
  -d "name=Carlos&email=carlos@example.com&message=Hello"

You should get {"success":true,"delivered":1,"failed":0} and the submission appears in the dashboard within a second.

5. (Optional) Redirect after submit

Set a redirect_url on the form to send users to a thank-you page after submission. Without it, the API returns JSON.

What submitters see when a form has no verified destinations

If every destination on the form is pending verification or disabled by its recipient, the public endpoint rejects the submission outright with HTTP 422:

{
  "error": "no_verified_destinations",
  "message": "This form has no verified destinations. The form owner must complete destination verification before submissions are accepted."
}

The submission is not stored — it isn't queued for later either. Your form's frontend should surface the message so the form-filler doesn't assume their data was accepted.

Editing a destination after the fact

• Editing only the label or routing rules keeps the destination verified.
• Editing an email destination to point at a different address resets verification and sends a fresh confirmation link to the new address. As a courtesy, the old address gets a notification that the destination was moved.
• Editing a Slack or webhook URL re-fires the test-ping with a fresh disconnect link. The destination stays in the verified state (same verified-on-add reasoning as creation).

If a recipient disconnects

When someone clicks the disconnect link in a Slack/webhook test-ping (or in the post-confirmation page for an email destination), the destination is marked Disabled by recipient in the dashboard and stops receiving submissions immediately. The form-owner can delete it and create a new one if needed. Disconnect links remain valid for 30 days from when they were issued.

Example: route enterprise leads to sales-Slack

Suppose your HTML form has a dropdown field interest with values starter, team, and enterprise. You can:

• Add a slack destination pointing at #sales, with a rule: interest equals enterprise
• Add a second email destination pointing at support@yourdomain.com, with no rules (everything else lands there)

Now every form submission is automatically routed — sales gets enterprise leads in Slack instantly; support handles the rest by email. No Zapier in the middle.

Supported operators

Enable it on a form

Open the form in your dashboard → Form settings → toggle Auto-reply to submitter. Configure which field holds the email, the subject, body, and optional Reply-To.

Template variables

Use {{ field_name }}in either subject or body — it's replaced with the value of that submission field. {{ form_name }}substitutes the form's display name.

Subject: Hi {{ name }}, we got your message

Body:
Hi {{ name }},

Thanks for reaching out via {{ form_name }}. We received your message:

  "{{ message }}"

Someone on our team will reply within 24 hours.

— The {{ form_name }} team

Deliverability — read this

• Auto-replies go out via your configured Resend account. The From address is whatever you set as RESEND_FROM_EMAIL on the server.
• For replies to land in real inboxes (not spam), the sender domain must be verified in Resend — same as transactional email.
• Set a Reply-Toto a real address you monitor; otherwise submitter replies go to the auto-reply's From address (often a noreply mailbox).
• Honeypot-flagged submissions never trigger the autoresponder.

If the autoresponder skips silently

A few reasons it might not fire:

• The configured field is missing or empty in the submission
• The recipient value isn't a valid email address
• Resend isn't configured on the server (missing API key)
• Your plan isn't in FEATURE_AUTORESPONDER_PLANS
• The instance has FEATURE_AUTORESPONDER=false

HTML form with file inputs

<form
  action="https://routepost.dev/api/f/YOUR-FORM-ID"
  method="POST"
  enctype="multipart/form-data"
>
  <input name="email" type="email" required />
  <textarea name="message" required></textarea>

  <!-- Single file -->
  <input name="attachment" type="file" />

  <!-- Multiple files -->
  <input name="screenshots" type="file" multiple />

  <button type="submit">Send</button>
</form>

Critical: include enctype="multipart/form-data" on the <form> tag. Without it, browsers send only the filenames, not the actual bytes.

Limits

• Max 25 MB per file
• Max 50 MB total per submission
• Any file type is accepted (no MIME filter at the server)
• Files are stored in Supabase Storage with public URLs
• If file uploads are disabled on the form, files are silently dropped (fields still process)

What destinations see

Each destination receives URLs to the uploaded files alongside the form data.

Email destination: file links appear below the data table in the email body.

Slack destination: an Attachments section with clickable links is appended to the message.

Webhook payload now includes:

{
  "form": "contact",
  "received_at": "2026-06-18T18:00:00.000Z",
  "data": { "email": "jane@acme.com", "message": "..." },
  "attachments": [
    {
      "name": "screenshot.png",
      "size": 12384,
      "type": "image/png",
      "url": "https://nansd…supabase.co/storage/v1/object/public/submission-files/…"
    }
  ]
}

Forms list

Landing screen after signing in. One card per form, with a quick submission count.

Form detail

Endpoint URL (with copy button), destinations management, and recent submissions — all on one page.

Recent submissions

Last 100 submissions per form, with IP and timestamp. Click a row to see the full payload.