How is shopping cart coupon code usage tracked in Magento?

In Magento, shopping cart coupon code usage is accurately tracked by recording it within the order details. When a coupon code is applied during the checkout process, it becomes associated with the order once it is completed. This linkage allows Magento to track not only the usage of the coupon but also provide insights into its effectiveness and how often it's being redeemed.

By storing the coupon code within the order records, Magento can manage a counter for how many times a particular coupon has been used. This functionality is essential for merchants to evaluate marketing campaigns, assess customer engagement, and make informed decisions about future promotional strategies. It also aids in avoiding any potential exploitation of coupon codes by enabling limitations on their usage.

Other options do not capture the comprehensive tracking mechanism in place for coupon codes. While session data does store temporary information related to a customer's cart, it does not persist beyond the session, and thus, does not provide a reliable method for tracking coupon usage over time. Storing code usage with just the invoice would limit the data available for comprehensive tracking. Email notifications are not a tracking mechanism; they are merely a method of communication. Hence, the most effective and logical means of tracking coupon code usage is by integrating it within the order data itself.