# Cal.com Webhooks

## When to Use This Skill

* How do I receive Cal.com webhooks?
* How do I verify Cal.com webhook signatures (the `x-cal-signature-256` header)?
* How do I handle `BOOKING_CREATED`, `BOOKING_RESCHEDULED`, or `BOOKING_CANCELLED` events?
* Why does my `MEETING_ENDED` handler not find `payload`?
* Why is my Cal.com webhook signature verification failing?

## Verification (core)

When a **secret** is set on the webhook, Cal.com sends `x-cal-signature-256` containing the
**lowercase hex** HMAC-SHA256 of the **raw request body**, keyed on that secret. There is no
`sha256=` prefix, no timestamp, and it is **not** Standard Webhooks. With a custom payload
template the body changes, but the signature is still over the exact bytes sent. Webhooks with
no secret send the literal value `no-secret-provided` — treat that as unsigned.

Node:

```javascript
const crypto = require('crypto');

function verifyCalComWebhook(rawBody, signatureHeader, secret) {
  if (!signatureHeader || !secret) return false;
  const expected = crypto.createHmac('sha256', secret).update(rawBody).digest('hex');
  try {
    return crypto.timingSafeEqual(Buffer.from(signatureHeader), Buffer.from(expected));
  } catch {
    return false; // length mismatch (e.g. "no-secret-provided") = invalid
  }
}

```

Python:

```python
import hmac, hashlib

def verify_cal_com_webhook(raw_body: bytes, signature_header: str | None, secret: str | None) -> bool:
    if not signature_header or not secret:
        return False
    expected = hmac.new(secret.encode(), raw_body, hashlib.sha256).hexdigest()
    return hmac.compare_digest(signature_header.encode(), expected.encode())

```

> **For complete handlers with route wiring, event dispatch, and tests**, see:
> 
> * [examples/express/](https://github.com/hookdeck/webhook-skills/tree/main/skills/cal-com-webhooks/examples/express/)
> * [examples/nextjs/](https://github.com/hookdeck/webhook-skills/tree/main/skills/cal-com-webhooks/examples/nextjs/)
> * [examples/fastapi/](https://github.com/hookdeck/webhook-skills/tree/main/skills/cal-com-webhooks/examples/fastapi/)

## Common Event Types

The event name is in the body's `triggerEvent` field (there is no event-type header).

| Event | Triggered When |
| --- | --- |
| `BOOKING_CREATED` | A booking is confirmed |
| `BOOKING_REQUESTED` | A booking needing confirmation is requested |
| `BOOKING_RESCHEDULED` | A booking is moved (`rescheduleUid` = old booking uid) |
| `BOOKING_CANCELLED` | A booking is cancelled (`cancellationReason`) |
| `BOOKING_REJECTED` | The host rejects a requested booking |
| `BOOKING_PAID` | Payment for a paid event succeeds |
| `MEETING_STARTED` / `MEETING_ENDED` | Fire at the booking's start/end time (**flat payload**) |
| `RECORDING_READY` | A Cal Video recording is available |
| `FORM_SUBMITTED` | A Routing Form is submitted |

> **For the full list**, see [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/cal-com-webhooks/references/overview.md) and
> [Cal.com's webhook docs](https://cal.com/docs/developing/guides/automation/webhooks).

## Payload Shape

Most events wrap data in `payload`; `MEETING_STARTED` and `MEETING_ENDED` put the booking fields
at the top level. Read `const data = event.payload ?? event`.

```json
{ "triggerEvent": "BOOKING_CREATED", "createdAt": "2024-01-01T00:00:00.000Z", "payload": { "uid": "...", "title": "...", "startTime": "...", "organizer": {}, "attendees": [] } }

```

## Important Headers

| Header | Description |
| --- | --- |
| `X-Cal-Signature-256` | Hex HMAC-SHA256 of the raw body (or `no-secret-provided`) |
| `X-Cal-Webhook-Version` | Payload version, e.g. `2021-10-20` |

## Environment Variables

```bash
CALCOM_WEBHOOK_SECRET=your_webhook_secret   # The "Secret" you set on the webhook in Cal.com

```

## Local Development

```bash
# Start tunnel (no account needed)
npx hookdeck-cli listen 3000 cal-com --path /webhooks/cal-com

```

Cal.com SaaS only accepts public HTTPS subscriber URLs (no `localhost`), so use the tunnel URL.

## Reference Materials

* [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/cal-com-webhooks/references/overview.md) - Cal.com webhook triggers and payload structure
* [references/setup.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/cal-com-webhooks/references/setup.md) - Create a webhook and secret in Cal.com settings
* [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/cal-com-webhooks/references/verification.md) - Signature verification details and gotchas