Payment Endpoint Overview

The payment endpoint is used to initiate, manage, and query transactions from a POS directly to a terminal.

All payment requests follow a similar pattern in their messaging:

1. POS initiates a payment method with a terminal.
2. The terminal acknowledges that payment method with the POS.
3. The terminal sends the payment method to the processor.
4. The terminal notifies the POS that the payment has been sent for processing.
5. The terminal sends back the final result of the payment method to the POS.

The PaymentId is a custom tracking string created by the POS to track during the lifespan of any specific payment

The MerchantData field is custom JSON object the POS can use to send any needed custom data that must be sent to the terminal or the processor.