Payment Processing: Stripe, Adyen, and the Payments Stack
Payment processing is the infrastructure that converts customer intent to merchant revenue. Choosing and implementing the right payments stack affects conversion rates, operational complexity, fraud management, international reach, and cost. Payment processing technology has become increasingly sophisticated — modern providers offer far more than basic card acceptance.
Payment Processing Architecture
- Payment gateway: Securely captures and transmits payment data between customer, merchant, and bank
- Payment processor: Processes the transaction between acquiring bank and card networks (Visa/Mastercard)
- Acquiring bank: Merchant's bank — receives funds from card networks
Modern payment providers (Stripe, Adyen) combine gateway, processing, and often acquiring in a single platform — simplifying integration and reducing complexity.
Major Providers
- Stripe: Excellent developer experience, comprehensive API, strong product suite (Billing, Connect, Radar fraud detection). Best for: startups, DTC, developers. Percentage + fixed per-transaction pricing.
- Adyen: Enterprise-focused, unified commerce (online + in-store), direct card scheme connections, lower interchange fees at scale. Best for: large enterprise, omnichannel, international.
- Braintree (PayPal): Good PayPal and Venmo integration, competitive pricing. Best for: marketplaces, strong PayPal customer base.
Buy Now Pay Later (BNPL)
BNPL (Klarna, Afterpay, Clearpay, Affirm) has become a significant payment method — particularly for fashion, electronics, and higher-value purchases. AOV increases of 20-40% are commonly reported. Integration is via provider-specific widgets; merchant cost is ~3-6% per transaction.