> ## Documentation Index
> Fetch the complete documentation index at: https://docs.4mica.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Quick Start

> Set up 4Mica webhooks quickly.

Start with one HTTPS endpoint and subscribe only to the events your product
needs.

## Create a handler

Your handler should preserve the raw request body, verify the signature, reject
invalid deliveries, deduplicate by event ID, and return a successful response
quickly.

```javascript Node.js theme={null}
app.post("/webhooks/4mica", rawBodyMiddleware, async (req, res) => {
  try {
    verifyWebhookSignature(req);
    const event = JSON.parse(req.body.toString("utf8"));

    if (await eventStore.has(event.id)) {
      return res.sendStatus(200);
    }

    await queue.publish("4mica-webhooks", event);
    await eventStore.record(event.id);

    return res.sendStatus(200);
  } catch (error) {
    return res.sendStatus(400);
  }
});
```

## Choose events

* Use [`collateral.deposited`](/webhooks/events/collateral-deposited) to refresh
  wallet collateral.
* Use [`guarantee.settled`](/webhooks/events/guarantee-settled) to reconcile
  payment completion.
* Use [`withdrawal.requested`](/webhooks/events/withdrawal-requested) to show a
  pending withdrawal.
* Use [`withdrawal.finalized`](/webhooks/events/withdrawal-finalized) to mark
  funds withdrawn.

## Test before production

1. Send a valid example payload from the event page.
2. Send the same event ID twice and confirm the second delivery has no effect.
3. Send events out of order and confirm your state remains correct.
4. Send a modified body with an invalid signature and confirm it is rejected.
5. Make the worker fail temporarily and confirm the event can be retried safely.

See [webhook security](/webhooks/security) before accepting live deliveries.