A Flutter plugin for working with the masterpass in-app API.


First add masterpass to as a dependency in your pubspec.yaml file.


Add the following keys to your Info.plist file, located in <project root>/ios/Runner/Info.plist:

<string>Your location will be used to prevent fraud.</string>


No configuration required - the plugin should work out of the box.


In order to use this plugin, a masterpass merchant account has to be setup on the Masterpass system - see to create a merchant account.

import 'package:flutter/material.dart';
import 'dart:async';

import 'package:masterpass/masterpass.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),

class HomePage extends StatelessWidget {
  ///The form key to use for the amount form.
  final GlobalKey<FormState> _formKey = GlobalKey<FormState>();

  /// The controller for the amount to pay.
  final TextEditingController _amountController = TextEditingController();

  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Masterpass Example App'),
      body: Padding(
        padding: const EdgeInsets.all(16.0),
        child: Center(
          child: Form(
            key: _formKey,
            child: Column(
              children: <Widget>[

  /// Returns the pay button.
  Widget _payButton(context) {
    return RaisedButton(
      child: Text("PAY"),
      onPressed: () async {
        if (_formKey.currentState.validate()) {
          //show loading dialog
            context: context,
            barrierDismissible: false,
            builder: (context) => SimpleDialog(
              title: Center(child: CircularProgressIndicator()),
              backgroundColor: Colors.transparent,

          String txnCode =
              await _getTransactionId(double.parse(_amountController.text));

          String apiKey =
              "enter-your-api-key-here"; // Your masterpass API key.
          String system = MasterpassSystem
              .TEST; // The masterpass system you want to use (TEST or LIVE)
          Masterpass masterpass = Masterpass(apiKey, system);
          CheckoutResult paymentResult = await masterpass.checkout(txnCode);

          if (paymentResult is PaymentSucceeded) {
            bool paymentVerified =
                await _verifyTransaction(txnCode, paymentResult.reference);
            Navigator.of(context).pop(); //pop the loading dialog
            if (paymentVerified) {
                content: Text("Payment succeeded."),
            } else {
                content: Text("Could not verify payment."),
          } else {
            Navigator.of(context).pop(); //pop the loading dialog
              content: Text("Payment failed."),

  /// Returns the amount field
  TextFormField _amountField() {
    return TextFormField(
      controller: _amountController,
      decoration: InputDecoration(
        labelText: "Amount",
      validator: (text) {
        try {
        } catch (e) {
          return "Please enter a valid amount";

        return null;

  /// Make a call to your backend to get a code for the transaction.
  Future<String> _getTransactionId(double amount) async {
    //You should replace this code with the call to your backend which requests a new transaction from masterpass.
    return Future.value("sample-transaction-code-from-your-backend");

  /// Make a call to your backend to verify the payment
  Future<bool> _verifyTransaction(String txnCode, String paymentRef) async {
    //You should replace this code with the call to your backend which verifies that the transaction was successful.
    return Future.value(true);

Response classes

The checkout method will return an instance of one of the following classes which will describe the result:

InvalidTxnCode - the transaction code used was invalid.

MasterpassError - an error occurred with asterpass before the payment was initiated.

UserCancelled - the user cancelled the transaction.

PaymentFailed - the payment failed (the reference field contains the payment reference)

PaymentSucceeded - the payment was successful (the reference field contains the payment reference)

Additional information:

The spec for the native android masterpass API can be found here

The spec for the native iOS masterpass API can be found here





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