# How It Works
source: https://developer.mastercard.com/transaction-notifications/documentation/how-it-works/index.md

## How It Works {#how-it-works}

### 1. Get Cardholder's Consent {#1-get-cardholders-consent}

In order to start receiving transaction notifications for your customers, it's important that you first obtain permission from consumers to receive this data. Note that if you are an issuer or a co-brand partner, you may have already obtained this permission as part of your card-holder account agreement. If you are a third party application and need to obtain consumer consent, please go through the [Consent \& Consumer Authentication](https://developer.mastercard.com/consent-management/documentation/) process before integrating with the Transaction Notifications API. This process to obtain consumer consent uses the same Mastercard \& Issuer experience that allows consumers to securely add their card to a digital wallet or confirm their identity when shopping online.

#### Consent flow using Mastercard UX {#consent-flow-using-mastercard-ux}

![Consent Flow](https://static.developer.mastercard.com/content/transaction-notifications/uploads/how-it-works-consent.jpg "Consent Flow")

#### Consent flow using Mastercard API {#consent-flow-using-mastercard-api}

![Consent Flow API](https://static.developer.mastercard.com/content/transaction-notifications/uploads/how-it-works-consent-api.jpg "Consent Flow API")
Tip: In the create consent part of this flow, you receive a **card reference**. This unique identifier will be used for matching transaction notifications to your customers.

### 2. Receive Real-time Transaction Notification {#2-receive-real-time-transaction-notification}

When the cardholder completes a transaction, Mastercard will send you the transaction details using an [outbound call](https://developer.mastercard.com/transaction-notifications/documentation/api-reference/transaction-notification-webhook/index.md) to the callback URL you provide during project configuration.

![Alert Flow](https://static.developer.mastercard.com/content/transaction-notifications/uploads/how-it-works-alert.jpg "Alert Flow")

## What's Next {#whats-next}

Review the [Quick Start Guide](https://developer.mastercard.com/transaction-notifications/documentation/quick-start-guide/index.md) to get an overview of integration and next steps.