Front Webhooks Skill

When to Use This Skill

• Setting up Front (Frontapp) application webhook handlers
• Debugging Front X-Front-Signature verification failures
• Responding to the Front X-Front-Challenge subscription validation request
• Understanding Front event types (inbound_received, outbound_sent, conversation_moved, assignee_changed, tag_added, new_comment_added) and payloads

Verification (core)

Front application webhooks have no official server SDK, so verify manually. Front signs X-Front-Request-Timestamp + ":" + rawBody with HMAC-SHA256 (key = your app's signing key), base64-encoded, delivered in the X-Front-Signature header. Use the raw request body — never JSON.parse before verifying.

const crypto = require('crypto');

function verifyFrontSignature(rawBody, timestamp, signature, secret) {
  const hmac = crypto.createHmac('sha256', secret);
  hmac.update(timestamp + ':');
  hmac.update(rawBody);                          // Buffer/string of the raw HTTP body
  const expected = hmac.digest('base64');
  try {
    return crypto.timingSafeEqual(Buffer.from(signature), Buffer.from(expected));
  } catch {
    return false;                                // length mismatch = invalid
  }
}

On subscription, Front first sends a validation request carrying an X-Front-Challenge header. Reply within 10s with HTTP 200 echoing the value — {"challenge": "<value>"} (JSON), challenge=<value> (form), or the raw value (text/plain).

For complete handlers with the challenge handshake, event dispatch, and tests, see:

• examples/express/
• examples/nextjs/
• examples/fastapi/

Common Event Types

Front webhook payloads carry the event name in the top-level type field.

For the full event reference, see Front Events.

Environment Variables

FRONT_WEBHOOK_SECRET=your_app_signing_key   # App signing key from the Front app settings

Local Development

# Start tunnel (no account needed)
npx hookdeck-cli listen 3000 frontapp --path /webhooks/frontapp

Reference Materials

• references/overview.md - Front webhook concepts and common events
• references/setup.md - Configure webhooks in Front, get the signing key
• references/verification.md - Signature verification and challenge details