# Pre Purchase
source: https://developer.mastercard.com/pay-with-rewards/documentation/use-cases/pre-purchase/index.md

## Short description {#short-description}

In this scenario, the cardholder decides to redeem points for a purchase prior to making the purchase. The cardholder turns Pay with Rewards on and then makes a transaction with the enrolled card as normal (there is no interruption to the merchant checkout flow). Pay with Rewards receives a copy of the approved transaction from the Mastercard network and processes it through Pay with Rewards rules. If it is eligible and there are sufficient points, a redemption occurs and a rebate is sent to the card.

Note: For more information on redemption through external point banks, see [integration models](https://developer.mastercard.com/pay-with-rewards/documentation/index.md#integration-models).

## Sequence diagram {#sequence-diagram}

Diagram pwr-pre-purchase

##### Following are the execution steps: {#following-are-the-execution-steps}

1. The consumer logs into the customer's app.
2. The customer authenticates the consumer.
3. The consumer turns Pay with Rewards on
4. The customer makes a PUT request to the /redeemers/{id}/preferences endpoint to update the consumers preferences
5. The request for updating the preferences has the following mandatory request parameters:
   * **id** : Unique identifier of the consumer
   * **redemption_type** : Redemption type should be PWR.
6. Mastercard Network API Gateway authenticates/authorizes the customer and routes the request to Pay with Rewards in the case of a valid customer.
7. The Pay with Rewards service validates the request parameters received via the `PUT /redeemers/{id}/preferences` endpoint.
8. The Pay with Rewards service updates the consumers preferences.
9. The Pay with Rewards service sends a response 200 back to the customer, assuming the request was valid.
10. The consumer makes a purchase
11. The Mastercard API Gateway sends a copy of the transaction to the Pay with Rewards service
12. The Pay with Rewards service then processes the redemption of points, if there is enough points available.
13. The Pay with Rewards service sends a notification to the consumer.