Payment Gateway

A payment gateway is the technology layer that sits between a merchant's checkout experience and the payment processing infrastructure behind it. When a customer submits payment information, whether on a website, in an app, or at a point of sale, the gateway receives that data, encrypts it, and transmits it to the appropriate Payment Processor or Acquirer for authorization. When the authorization response comes back, the gateway relays the result to the merchant and, where applicable, to the customer.

Gateways perform several critical functions beyond simple data relay. They tokenize sensitive card data to minimize PCI Scope, handle the communication protocols required by different card networks, manage the formatting and transmission of transaction messages, and often provide the developer-facing API (Application Programming Interface) that merchants use to build payment flows into their products.

The line between a gateway and a processor has blurred significantly in modern payments. Platforms like Stripe, Adyen, and Braintree function as gateway, processor, and Acquirer simultaneously. In that model, a merchant connects to a single platform and that platform handles everything. In contrast, many enterprise merchants maintain a gateway relationship that is separate from their acquiring relationship, giving them the flexibility to switch acquirers without rebuilding their checkout integration.

This flexibility, maintaining gateway connectivity independently of any single processor or acquirer, is the foundational principle behind Payment Orchestration. A Payments Orchestration Platform like Spreedly sits above the gateway layer, connecting to hundreds of gateways and payment services through a single integration, and routing transactions intelligently across them.