# Tailscale Webhooks

## When to Use This Skill

* How do I receive Tailscale webhooks?
* How do I verify the `Tailscale-Webhook-Signature` header?
* How do I handle `nodeCreated`, `nodeNeedsApproval`, or `nodeKeyExpiringInOneDay` events?
* How do I react to `policyUpdate` or `userCreated` events in a tailnet?
* Why is my Tailscale webhook signature verification failing?

## Verification (core)

Tailscale sends a `Tailscale-Webhook-Signature` header of the form `t=<unix seconds>,v1=<hex>`.
`v1` is the hex HMAC-SHA256 of `"<t>.<raw body>"`, keyed with the webhook secret as a raw UTF-8
string (e.g. `tskey-webhook-xxxxx`, case-sensitive, shown once at creation). `v1` is the only
scheme. Docs suggest rejecting timestamps more than 5 minutes old, but retries (Tailscale's hourly ones and
Hookdeck's) keep the original `t`, so the window is opt-in here (`TAILSCALE_TIMESTAMP_TOLERANCE_SECONDS`, default `0`).
Always sign over the **raw body**.

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

// toleranceSeconds = 0 (default) skips the timestamp window; a positive value opts in
function verifyTailscaleWebhook(rawBody, header, secret, toleranceSeconds = 0) {
  if (!header) return false;
  const parts = header.split(',').map((p) => p.split('='));
  const t = parts.find(([k]) => k === 't')?.[1];
  const sigs = parts.filter(([k]) => k === 'v1').map(([, v]) => v);
  if (!t || !/^\d+$/.test(t) || sigs.length === 0) return false;
  if (toleranceSeconds > 0 && Math.abs(Date.now() / 1000 - Number(t)) > toleranceSeconds) return false; // opt-in replay window
  const expected = crypto.createHmac('sha256', secret).update(`${t}.`).update(rawBody).digest('hex');
  return sigs.some((sig) => {
    try { return crypto.timingSafeEqual(Buffer.from(sig), Buffer.from(expected)); }
    catch { return false; } // length mismatch
  });
}

```

Tailscale has no verification SDK (only a [Go example](https://github.com/tailscale/tailscale/blob/main/docs/webhooks/example.go)), so verification is manual in every framework.

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

## Common Event Types

The body is a **JSON array** of events (several may be batched in one request). Route on each event's `type`:

| Event | Triggered When | Common Use Cases |
| --- | --- | --- |
| `nodeCreated` | A node joins the tailnet | Inventory, onboarding automation |
| `nodeNeedsApproval` | A node needs admin approval | Open an approval ticket |
| `nodeApproved` | A node was approved | Close the approval ticket |
| `nodeKeyExpiringInOneDay` | A node key expires in under a day | Notify the device owner |
| `nodeDeleted` | A node was deleted (incl. ephemeral nodes) | Remove from inventory |
| `policyUpdate` | The tailnet policy file changed | Audit access-control changes |
| `userCreated` | A user was created | Provision downstream accounts |
| `test` | You clicked **Send test event** | Confirm the endpoint works |

More types (`nodeKeyExpired`, `userRoleUpdated`, `webhookUpdated`, ...) are listed in [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/tailscale-webhooks/references/overview.md).

## Environment Variables

```bash
TAILSCALE_WEBHOOK_SECRET=tskey-webhook-xxxxx   # Shown once when the endpoint is created
TAILSCALE_TIMESTAMP_TOLERANCE_SECONDS=0       # Optional replay window; a positive value opts in

```

## Local Development

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

```

## Reference Materials

* [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/tailscale-webhooks/references/overview.md) - Tailscale webhook concepts, events, payload shape
* [references/setup.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/tailscale-webhooks/references/setup.md) - Create an endpoint in the admin console and get the secret
* [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/tailscale-webhooks/references/verification.md) - Signature verification details and gotchas