# What is an event?

An Event will contain a full copy of the resource under the resource key. The resource object will contain an `object` key which will be the name of the Paystand resource. A full spec can be found under that resource's API docs. For example, if the object is `payment` you can find the full specs under [Payment resource](https://developers.paystand.com/reference/the-payment-resource).

Any changes to properties in the following Paystand resources will cause an event to be emitted to a registered client system: [Customer](https://developers.paystand.com/reference/retrieve-customer), [Payment](https://developers.paystand.com/reference/retrieve-payment), [Refund](https://developers.paystand.com/reference/retrieve-refund), [Dispute](https://developers.paystand.com/reference/retrieve-dispute), [Withdrawal](https://developers.paystand.com/reference/retrieve-withdrawal)

Event webhook can be configured on a per-customer basis by updating the [Customer's settings](https://developers.paystand.com/reference/customer-settings).

Paystand highly recommends that customers verify that any received HTTP POST event callback originated at Paystand by [retrieving the event back](https://developers.paystand.com/reference/retrieve-event) from its systems by using the supplied id.

## THE EVENT OBJECT

```json
{
  "resource": {
    "object": "payment",
    "id": "3kramjln354zmhcl17bfft6j",
    "amount": "15.00",
    "currency": "USD",
    "externalId": "pay01",
    "payerId": "h2ficw8bkirmlece404ulf14",
    "payer": {...},
    "fees": [{...}],
    "holds": [{...}],
    "sourceId": "31e48fdzmvidlxmdqr23r1op",
    "sourceType": "Card",
    "ownerId": "0c7c56vbmzcwiw94wdl9k1ec",
    "status": "posted",
    "created": "2016-09-09T18:37:51.000Z",
    "lastUpdated": "2016-09-09T18:37:54.000Z"
  },
  "diff": {
    "previous": {
      "object": "payment",
      "id": "3kramjln354zmhcl17bfft6j",
      "amount": "15.00",
      "currency": "USD",
      "externalId": "pay01",
      "payerId": "h2ficw8bkirmlece404ulf14",
      "payer": {},
      "fees": [{..}],
      "holds": [{..}],
      "sourceId": "31e48fdzmvidlxmdqr23r1op",
      "sourceType": "Card",
      "ownerId": "0c7c56vbmzcwiw94wdl9k1ec",
      "status": "processing",
      "created": "2016-09-09T18:37:51.000Z",
      "lastUpdated": "2016-09-09T18:37:52.000Z",
      "customValues": []
    },
    "changes": {
      "holds": [{..}],
      "status": "posted",
      "lastUpdated": "2016-09-09T18:37:54.000Z"
    }
  },
  "urls": [
    "http://requestb.in/w1oosfw1"
  ],
  "created": "2016-09-09T18:37:55.000Z",
  "lastUpdated": "2016-09-09T18:37:55.000Z",
  "status": "active",
  "id": "g6lq7pdu0mjqhsmwidxu5xmu",
  "object": "event"
}
```

| Parameter | Description |
| --- | --- |
| id | The unique identifier for the event. |
| object | Will have value "event" indicating that the object is an event response. |
| resource | Embedded resource object. This is the current resource after any updates. |
| resource.object | This value will determine the resource that this event is for.<br>For example: `payment` will represent a [Payment resource](https://developers.paystand.com/reference/the-payment-resource).<br>**A full spec of attributes can be found under the corresponding resources page.** |
| diff.previous | The previous state of the resource before the updates. |
| diff.changes | An object containing the key-value pairs of parameters that have changed during the resource update. |
| urls | An array of urls the event is registered to be sent to. |
| created | The date the event was created. |
| lastUpdated | The date the event was last updated.