How can cashback be implemented in a banking application? Suggest implementation options.

To implement cashback in a banking application, several options can be considered:

1. Percentage of the purchase amount — a percentage is calculated for each transaction and returned to the customer's account.
2. Categorical cashback — increased cashback for certain categories of goods or services.
3. Promotions and bonuses — temporary promotions with increased cashback.
4. Accumulated cashback — cashback accumulates and can be used later or exchanged for bonuses.

Technically:

• Store cashback rules and accrual history in the database.
• Calculate the cashback amount according to the specified rules during transaction processing.
• Automatically or upon request, credit the cashback to the customer's account.

This can be implemented via a microservice that listens to transaction events and calculates cashback, or by integrating the logic into the main payment processing service.