The KhadashPay project is an open-source payment system. I made it to provide the business owners with the opportunity to easily deploy a card payment system in their store without having to buy an expensive terminal, pay fees for each transaction, and waste time and resources dealing with the bank.
As for the customers of the store where the KhadashPay is deployed, Khadash pay doesn't keep any logs whatsoever and doesn't require a bit of your personal information to create an account.
You can find the tutorials here:
V2.0 (ESP32 Version): https://www.instructables.com/KhadashPay-V20/
V2.0 (Raspberry Pi Pico Version): https://www.instructables.com/KhadashPay-V20-Raspberry-Pi-Pico-Version/
V3.0 (STM32F401CCU6 Version): https://www.instructables.com/KhadashPay-V30-STM32F401CCU6-Version/
V3.0 (ESP32 Version): https://www.instructables.com/KhadashPay-V30/
V3.5 (ESP32 Version): https://www.instructables.com/KhadashPay-V35/