# Zendesk Webhooks

## When to Use This Skill

* Setting up Zendesk webhook handlers
* Debugging Zendesk signature verification failures
* Understanding Zendesk event subscriptions vs. trigger/automation webhooks
* Handling ticket, user, or organization events like `zen:event-type:ticket.created`

## Verification (core)

Zendesk signs every webhook with HMAC-SHA256, base64-encoded. The signed
message is the timestamp concatenated directly with the raw request body
(no separator): `base64(HMAC_SHA256(timestamp + body))`. Zendesk does not
follow the Standard Webhooks spec and ships no official verification SDK, so
verify manually with the language's crypto primitives.

Two headers are sent:

* `X-Zendesk-Webhook-Signature` — the base64 signature
* `X-Zendesk-Webhook-Signature-Timestamp` — the timestamp that is prepended to the body

Use the raw body — don't `JSON.parse` first. Some requests (e.g. `GET`/`DELETE`
methods on a webhook) have no body, so account for an empty body.

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

function verifyZendeskWebhook(rawBody, signature, timestamp, secret) {
  const hmac = crypto.createHmac('sha256', secret);
  hmac.update(timestamp);        // timestamp first...
  hmac.update(rawBody);          // ...then the raw body (Buffer), no separator
  const expected = hmac.digest('base64');
  try {
    return crypto.timingSafeEqual(Buffer.from(expected), Buffer.from(signature));
  } catch {
    return false;                // length mismatch = invalid
  }
}

```

The signing secret comes from `GET /api/v2/webhooks/{webhook_id}/signing_secret`
(or Admin Center → the webhook → Reveal secret). Test webhooks (before
creation) always use the static secret `dGhpc19zZWNyZXRfaXNfZm9yX3Rlc3Rpbmdfb25seQ==`.

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

## Two Webhook Models

Zendesk webhooks work in one of two mutually exclusive modes:

1. Event subscriptions — the webhook subscribes to `zen:event-type:*` events.
  Zendesk sends a CloudEvents-style envelope with a `type` field you dispatch on.
2. Connected to a trigger or automation — the payload is custom JSON you
  define in the trigger/automation body (no `type` field).

A single webhook cannot both subscribe to events and be connected to a trigger.
Signature verification is identical for both.

## Common Event Types (event subscriptions)

| Event `type` | Triggered When |
| --- | --- |
| `zen:event-type:ticket.created` | A ticket is created |
| `zen:event-type:ticket.status_changed` | A ticket's status changes |
| `zen:event-type:ticket.comment_added` | A comment is added to a ticket |
| `zen:event-type:ticket.priority_changed` | A ticket's priority changes |
| `zen:event-type:ticket.agent_assignment_changed` | A ticket's assignee changes |
| `zen:event-type:user.created` | A user is created |
| `zen:event-type:organization.created` | An organization is created |

> For the full event reference, see [Zendesk webhook event types](https://developer.zendesk.com/api-reference/webhooks/event-types/webhook-event-types/).

## Environment Variables

```bash
ZENDESK_WEBHOOK_SECRET=your_signing_secret_here   # from GET /api/v2/webhooks/{id}/signing_secret

```

## Local Development

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

```

## Reference Materials

* [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/zendesk-webhooks/references/overview.md) - Zendesk webhook concepts, event subscriptions vs. triggers
* [references/setup.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/zendesk-webhooks/references/setup.md) - Admin Center configuration, getting the signing secret
* [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/zendesk-webhooks/references/verification.md) - Signature verification details and gotchas