# Why Fulfil From Webhooks — Stripe Payments

Source: https://www.skillbyai.com/en/stripe-payments/w-why

> Events are the source of truth.

## Events instead of redirects

A **webhook** is an HTTPS POST that Stripe sends to your endpoint when something happens on your account. Each request carries an **Event** object with a `type` and the related object in `data.object`. Many payments finish asynchronously (bank debits, 3D Secure, delayed methods), and browsers can close before a redirect, so the reliable signal is the event: `checkout.session.completed` for Checkout, `payment_intent.succeeded` or `payment_intent.payment_failed` for PaymentIntents, and `checkout.session.async_payment_succeeded` for delayed methods used in Checkout. You register endpoints and choose which event types to receive in the Dashboard or via the API.

## Let Stripe tell you what happened

Stripe sends signed event notifications to your endpoint, and your server fulfils orders from them.

![Three ideas: why fulfilment belongs in webhooks, verifying signatures, and handling retries and local testing.](assets/figures/stripe-payments/section-3-map.svg) — Figure 3.1 — Event, signed request, verification and fulfilment.

## Routing events by type

The core of a webhook handler.

```javascript
switch (event.type) {
  case 'checkout.session.completed': {
    const session = event.data.object;
    if (session.payment_status === 'paid') await fulfilOrder(session.client_reference_id);
    // for delayed methods, wait for checkout.session.async_payment_succeeded
    break;
  }
  case 'checkout.session.async_payment_succeeded':
    await fulfilOrder(event.data.object.client_reference_id);
    break;
  case 'payment_intent.payment_failed':
    await notifyPaymentFailed(event.data.object.id);
    break;
  default:
    // ignore event types you do not handle
}

```

## A courier's delivery confirmation

A customer saying "I paid" is like someone telling you a parcel arrived; the webhook is the courier's signed delivery receipt.

**Quiz:** Why should order fulfilment happen in a webhook handler rather than on the success page?

- [x] The customer may never reach the success page, and some payments complete later
- [ ] Webhooks are faster than redirects in every case
- [ ] Success pages cannot read query strings
- [ ] Stripe forbids success pages

*Answer:* The customer may never reach the success page, and some payments complete later. Events arrive even if the browser closes, and they cover asynchronous payment methods.