# Update Payment Request
Describes a request to update a payment using
[UpdatePayment](../../doc/api/payments.md#update-payment).
## Structure
`UpdatePaymentRequest`
## Fields
| Name | Type | Tags | Description |
| --- | --- | --- | --- |
| `payment` | [`Payment \| undefined`](../../doc/models/payment.md) | Optional | Represents a payment processed by the Square API. |
| `idempotencyKey` | `string` | Required | A unique string that identifies this `UpdatePayment` request. Keys can be any valid string
but must be unique for every `UpdatePayment` request.
For more information, see [Idempotency](https://developer.squareup.com/docs/build-basics/common-api-patterns/idempotency).
**Constraints**: *Minimum Length*: `1`, *Maximum Length*: `45` |
## Example (as JSON)
```json
{
"idempotency_key": "956f8b13-e4ec-45d6-85e8-d1d95ef0c5de",
"payment": {
"amount_money": {
"amount": 1000,
"currency": "USD"
},
"tip_money": {
"amount": 100,
"currency": "USD"
},
"version_token": "ODhwVQ35xwlzRuoZEwKXucfu7583sPTzK48c5zoGd0g6o",
"id": "id6",
"created_at": "created_at4",
"updated_at": "updated_at2"
}
}
```