# Polar Webhooks

## When to Use This Skill

* How do I receive Polar webhooks?
* How do I verify Polar webhook signatures?
* How do I handle `order.paid`, `subscription.created`, or `checkout.updated` events?
* Why is my Polar webhook signature verification failing?
* Setting up a Polar webhook endpoint in organization settings

## Verification (core)

Polar follows the [Standard Webhooks](https://www.standardwebhooks.com/) spec. Each request
carries three headers — `webhook-id`, `webhook-timestamp`, and `webhook-signature` — and the
signature is an HMAC-SHA256, base64-encoded, over `{webhook-id}.{webhook-timestamp}.{body}`.
Always verify against the raw request body — don't `JSON.parse` first.

Use Polar's official SDK helpers, which parse and verify in one call:

Node (`@polar-sh/sdk`):

```javascript
const { validateEvent, WebhookVerificationError } = require('@polar-sh/sdk/webhooks');

try {
  // rawBody: Buffer/string of the raw HTTP body; headers: the request headers object
  const event = validateEvent(rawBody, headers, process.env.POLAR_WEBHOOK_SECRET);
  // event.type -> e.g. "order.paid"; event.data -> the resource
} catch (err) {
  if (err instanceof WebhookVerificationError) {
    // invalid signature -> respond 400/403
  }
}

```

Python (`polar-sdk`):

```python
from polar_sdk.webhooks import validate_event, WebhookVerificationError

try:
    event = validate_event(body=raw_body, headers=request.headers,
                           secret=os.environ["POLAR_WEBHOOK_SECRET"])
except WebhookVerificationError:
    ...  # invalid signature -> respond 400/403

```

> Secret gotcha: The Standard Webhooks spec expects the secret to be base64-encoded before
> signing. The Polar SDKs base64-encode your dashboard secret for you, so pass the secret
> as-is. For a manual verifier, base64-encode the secret first (see
> [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/polar-webhooks/references/verification.md)). Polar secrets are user-set or
> randomly generated — they are not `whsec_`-prefixed.

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

## Common Event Types

| Event | Triggered When |
| --- | --- |
| `checkout.updated` | A checkout session changes state (e.g. confirmed) |
| `order.created` | A new order is created (purchase or subscription renewal) |
| `order.paid` | An order is fully paid |
| `order.refunded` | An order is refunded |
| `subscription.created` | A new subscription is created |
| `subscription.canceled` | A subscription is set to cancel at period end |
| `subscription.revoked` | A subscription ends and access should be revoked |
| `customer.state_changed` | A customer's state changes (subscriptions/benefits) |

> For the full list of 30+ events, see [Polar Webhook Events](https://polar.sh/docs/integrate/webhooks/events).

## Environment Variables

```bash
POLAR_WEBHOOK_SECRET=your_webhook_signing_secret   # From the endpoint settings in Polar

```

## Local Development

```bash
# Start a tunnel to your local handler (no account needed)
npx hookdeck-cli listen 3000 polar --path /webhooks/polar

```

Polar also ships a first-party tunnel: `polar listen http://localhost:3000/`, and a sandbox
environment (`sandbox.polar.sh`) for test purchases without real charges.

## Reference Materials

* [references/overview.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/polar-webhooks/references/overview.md) - What Polar webhooks are, common events
* [references/setup.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/polar-webhooks/references/setup.md) - Dashboard configuration and signing secret
* [references/verification.md](https://github.com/hookdeck/webhook-skills/blob/main/skills/polar-webhooks/references/verification.md) - Signature verification details and gotchas