Payment Gateway Integration

In India, payment integration is not a simple task. The Indian payments ecosystem spans UPI, net banking, credit and debit cards, EMI, Buy Now Pay Later, wallets, and QR-code-based payments across dozens of providers. Getting this right is the difference between a checkout that converts and one that leaks revenue. At Core Chunk, payment gateway integration is one of our most requested and most refined specialisations — built on the reality of Indian payment behaviour, compliance requirements, and the technical quirks of each provider's API.

The Indian Payments Landscape India's digital payments ecosystem is unique. UPI now accounts for over 50% of digital transactions in India. Razorpay, PayU, and CCAvenue dominate the payment aggregator market. PhonePe, Google Pay, and Paytm are the dominant UPI apps. Customers expect EMI options on purchases above ₹3,000. Net banking is still widely used for high-value B2B transactions. International customers need Stripe or PayPal. A complete Indian checkout must handle all of this seamlessly from a single integration layer.

Razorpay Integration Razorpay is our most frequently integrated payment gateway. We implement the full Razorpay suite: standard checkout, Razorpay Payment Links for WhatsApp and SMS payment collection, Razorpay Subscriptions for SaaS and subscription commerce, Razorpay Smart Collect for automated bank transfer reconciliation, Razorpay Route for marketplace settlements, and UPI Autopay for recurring mandates. We handle webhook signature verification, idempotency for retry safety, and refund processing via the Razorpay API.

PhonePe, PayU, and CCAvenue We integrate PhonePe's PG SDK for UPI and card payments, PayU's Bolt for embedded checkout, and CCAvenue for businesses that require a bank-agnostic aggregator with strong net banking coverage. For businesses serving Tier 2 and Tier 3 cities, CCAvenue and PayU often provide better success rates than newer aggregators.

Stripe for International Commerce For Indian businesses selling to international customers, Stripe provides the most reliable global payment infrastructure. We implement Stripe's Payment Intents API, 3D Secure authentication, Stripe Connect for marketplace payouts, and webhook handling for asynchronous payment confirmation. We also configure Stripe's currency conversion and tax (Stripe Tax) for businesses selling across multiple countries.

Smart Payment Routing For high-volume stores, we build payment routing logic that dynamically selects the gateway with the highest success rate for each transaction based on the payment method, card issuer, and customer location. This "Smart Routing" layer sits above individual gateway integrations and can increase payment success rates by 5-15% — a significant revenue impact at scale.

PCI-DSS Compliance and Security We implement all payment integrations with PCI-DSS compliance in mind: no card data touches your server (all sensitive data goes directly to the gateway's tokenisation layer), HTTPS/TLS enforced on all payment endpoints, CSRF protection on checkout forms, and webhook signature verification to prevent spoofed payment confirmations. We also implement rate limiting on payment initiation endpoints to prevent carding attacks.