Cross-Platform Mobile Engineering with React Native & Expo

┌───────────────────────────────────────────────────────────┐
│              Single TypeScript Codebase                   │
│   (Shared Types, Business Logic & API Client with Web)    │
└─────────────┬───────────────────────────────┬─────────────┘
              │                               │
              ▼                               ▼
┌───────────────────────────┐   ┌───────────────────────────┐
│     Apple iOS (Store)     │   │    Google Android (Store) │
│ (Native Swift Bridge/EAS) │   │ (Native Kotlin Bridge/EAS)│
└─────────────┬─────────────┘   └─────────────┬─────────────┘
              │                               │
              └───────────────┬───────────────┘
                              ▼
        ┌───────────────────────────────────────────┐
        │   Expo EAS Instant Over-The-Air Updates   │
        │      (Zero App Store Review Delays)       │
        └───────────────────────────────────────────┘

// services/payment/RazorpayService.ts
import RazorpayCheckout from 'react-native-razorpay';
import { Alert } from 'react-native';

interface PaymentOptions {
  orderId: string;
  amountInPaise: number;
  userEmail: string;
  userPhone: string;
  businessName: string;
}

export async function initiateNativeUpiPayment(options: PaymentOptions): Promise<string> {
  const checkoutConfig = {
    description: 'Order Payment',
    image: 'https://kaamlabs.in/images/brand/logo-square.png',
    currency: 'INR',
    key: process.env.EXPO_PUBLIC_RAZORPAY_KEY_ID || '',
    amount: options.amountInPaise,
    name: options.businessName,
    order_id: options.orderId,
    prefill: {
      email: options.userEmail,
      contact: options.userPhone,
    },
    theme: { color: '#FF4D00' },
  };

  try {
    const data = await RazorpayCheckout.open(checkoutConfig);
    // Returns razorpay_payment_id, razorpay_order_id, razorpay_signature
    return data.razorpay_payment_id;
  } catch (error: any) {
    if (error.code === 2) {
      Alert.alert('Payment Cancelled', 'You cancelled the transaction.');
    } else {
      Alert.alert('Payment Failed', error.description || 'Unable to process payment');
    }
    throw error;
  }
}