Example implementation using React Native Library:

 import { PosBuddy } from 'react-native-thumbzup-pos-buddy';
 ​
 const posBuddy = new PosBuddy();
 ​
 // Your device identifier is displayed in the Thumbzup PoS Buddy client on your payment device.
 posBuddy.connect('device identifier', (nextStatus: PbStatus) =>
   console.log('Connection status', nextStatus)
 );
 ​
 // Authenticate.
 posBuddy.setPosId(appKey);
 posBuddy.setMerchantId(merchantId);
 posBuddy.setAuthenticationKey(authenticationKey);
 posBuddy.doPosAuth(({ secretKey, accessKey }) => {
   // Keep `obj.authenticationKey` for your session.
 });
 ​
 // Make a payment.
 posBuddy.doPayment(totalAmountInCents, (obj: any) => {
   // View the payment outcome in the `obj.receiptBundle`.
 });