Payment Gateway Integration Suite

Across multiple client projects, I have built and integrated a comprehensive suite of payment gateway solutions handling everything from simple one-time payments to complex recurring subscription billing. Razorpay integration spans UPI, net banking, cards, and EMI options with Razorpay Subscriptions for automated recurring billing. Apple Pay was integrated for iOS-first e-commerce clients using the Payment Request API with server-side session validation compliant with Apple's merchant verification requirements. HDFC SmartGateway integration was built for enterprise clients needing bank-grade payment infrastructure with 3D Secure authentication, multi-currency support, and NPCI compliance. Amex integration covers corporate card acceptance with enhanced data Level 2/3 for B2B clients. Fasthub (fast checkout) was integrated as a one-click checkout solution reducing cart abandonment. Each gateway integration includes: secure server-side signature verification, idempotent webhook processing to prevent duplicate transactions, automatic retry logic for failed payments, and a unified transaction dashboard reconciling payments across all gateways.