Event Callbacks

The SDK triggers event callbacks in the EMV Core SDK to notify the application of specific events during the transaction lifecycle. They enable developers to respond dynamically to changes in transaction status and system events. These callbacks provide real-time updates, ensuring seamless communication between the SDK and the application.

These are the available callbacks.

CardTokenReceived
ReaderMessageEvent
SystemStatusChanged
TransactionComplete

You can read a more detailed description of each Callback event in the sections below.

`CardTokenReceived`

This event is triggered after a card token is successfully retrieved.

Open loop example:

{"jsonrpc":"2.0", "method": "CardTokenReceived", "params": {"status": "OK",
"errorCode": 0, "errorDescription": "", "CardToken":
"WSAr79nKPywW3INXrWvr6IL3vgTgSJlwZBgseKDmMHM=", "PartialPan": ""}, "id": 702}

Closed loop example:

"LocalCLP", "errorCode": 0, "errorDescription": "", "CardToken": "73D0D1C5",
"PartialPan": ""}, "id": 702}

`ReaderMessageEvent`

This callback provides updates on user interface messages from the card reader.

{"jsonrpc": "2.0", "method": "ReaderMessageEvent", "params": {"index": 36,
"line1": "Authorizing", "line2": "Please wait"}}

Parameter	Description
index	The index of the message – Decimal value according to the Message Index table. Note: The actual text presented on the reader display depends on the Kiosk configuration and may differ from the table values.

`SystemStatusChanged`

🚧
This method is only available for the Android operating system.

The SystemStatusChanged event indicates changes in the SDKs or connected devices' operational state.

void onTransactionComplete(TransactionResult result);

SystemStatus is an enumeration representing the current state of the system. See the possible result values in the table below:

Result	Description
`Ready`	The SDK is ready for transactions.
`NotReady`	The SDK is not operational.
`PaymentTransaction`	A transaction is currently in progress.
`Update`	A firmware or configuration update is ongoing.

`TransactionComplete`

The TransactionComplete is called by EMV Core when the transaction is complete and either succeeds or fails. Contains the details required by the POS to print a receipt and to link transactions to sale events

Open loop request:

{
 "jsonrpc": "2.0",
 "method": "TransactionComplete",
 "params": {
   "status": "OK",
   "errorCode": 0,
   "errorDescription": "",
   "transactionId": "2046651064",
   "authorizationDetails": {
     "AmountAuthorized": 4.5,
     "AmountRequested": 4.5,
     "AuthorizationCode": "",
     "PartialPan": "541333******4111",
     "CardType": "MasterCard",
     "IsTransactionApproved": true,
     "eReceipt": "[https://s.wee.ai/tr/...eIHT](https://s.wee.ai/tr/...eIHT)",
     "Card_ID": "",
     "Card_Balance": 0.0,
     "RRN": "",
     "TransactionDbID": "2046651064",
     "Transaction_Referance": "2046651064",
     "CardToken": "5VXkNqtUDJBxQj9p/qTGt74jWaPHlRs7xxWa1Yu0gDI=",
     "Additional_Parameters": {
       "SiteId": "1",
       "EntryMode": "4",
       "MachineAuTime": "2025-09-03T14:12:30.006",
       "NayaxTransactionId": "2046651064"
     }
   }
 },
 "id": 701
}

Closed loop request:

   {"jsonrpc":"2.0", "method": "TransactionComplete", "params":
{"status": "LocalCLP", "errorCode": 0, "errorDescription": "",
"transactionId": "4701113B", "authorizationDetails":
{"CardType": "Mifare", "Card_ID": "4701113B", "Card_Balance": 0.00,
"CardToken": "4701113B", "Additional_Parameters": {}}}, "id": 701}

Response:

{"jsonrpc":"2.0", "result":true, "id":701}