Single Session with Pre-Selection

In the Pre-selection flow, the customer first selects a product before proceeding to initiate payment. The vending machine remains idle, waiting for product selection. Once the user chooses a product, the payment terminal requests card authorization and, upon approval, dispenses the product.

This method ensures a smooth, secure transaction by separating product selection from payment authorization within a single vending session.

Payment Flow

Visualize the Pre-selection process with the diagram below, which illustrates each step of the single vending session flow, from product selection to payment authorization and dispensing.

Below is a breakdown of the diagram:

1. The Nayax Device sends a message to the Card Holder: "Please Select a Product."
2. The Card Holder selects a product for the vending machine.
3. The vending machine SDK sends a vending request to the Nayax Device.

   In C:
   vmc_vend_vend_request(vend_session_t *session)
   
   In C#:
   vmc_instance.vend.vend_request(session);
   
   In Java:
   m_vmc.vend.vend_request(m_sessions[m_active_session]);

4. The Nayax Device sends a message to the Card Holder: "Please Present Card."
5. Card Holder presents their payment card.
6. The Nayax Device sends an authorization request to the Nayax Server.
7. The Nayax Server forwards the authorization request to the Billing Provider.
8. The Billing Provider sends an authorization response (approved) to the Nayax Server.
9. The Nayax Server sends the authorization response (approved) back to the Nayax Device.
10. The vending machine SDK handles transaction data

    In C:
    vmc_vend_event_handler_cb(vm_vend_event_on_transaction_info)
    
    // WIP!!! needs to add the calls of the functions
    In C#:
    onTransactionInfo(data)
    
    In Java
    onTransactionInfo

11. The SDK triggers vend approved events (vmc_vend_event_handler_cb(vm_vend_event_on_vend_approved)).
12. The vending machine dispenses the product.
13. The SDK reports vend success (vmc_vend_vend_status(&session, __true)) and completes the vend session (vmc_vend_vend_session_complete_lowlevel()).
14. Message to Card Holder: "Please Take Product."
15. The Nayax Device sends a settlement request to the Nayax Server.
16. The Nayax Server forwards the settlement request to the Billing Provider.
17. The Billing Provider sends a settlement response (OK) to the Nayax Server.
18. The Nayax Server returns the settlement response (OK) to the Nayax Device.
19. The vending session ends.
20. Message to Card Holder: "Thank you & Goodbye."

See Also