Payment Gateway Integration

What payment gateway integration is

Payment gateway integration is the work of connecting a checkout or business system to a payment gateway. The gateway captures and transmits payment information, while the integration lets your website or app send payment requests and receive results. A payment gateway is the service; integration is how you connect it to your business.

The connection can support more than card authorization. Depending on its setup, it can handle capture, refunds, payment-status updates, settlement records, and reconciliation. For example, connecting a payment to an order number lets your staff match the payment record with the order and later compare it with a payout.

A successful connection is more than an approved payment, your order, payment status, and settlement records must agree.

How the connection works

You can connect a gateway with a hosted checkout page, embedded payment fields, a platform plugin, or a direct API integration. A hosted payment page sends the customer to a page controlled by the gateway, keeping card data off your website's servers. Embedded fields keep checkout on your site while the gateway handles sensitive card data. A direct API gives you more control over the checkout flow, but requires development and ongoing maintenance.

After a customer submits payment details, the integration sends the request for processing and returns a status to your checkout. A browser redirect or API response alone does not always confirm final payment success. Timeouts, delayed notifications, or duplicate notifications can leave an order and payment with different statuses, so your system needs to verify and match updates to the right order.

What it means for costs and security

Integration does not set the card networks' interchange rates. Your costs come from the gateway or payment provider's fees, any processor markup, and the developer time needed to build and maintain the connection. Provider pricing can include transaction or monthly fees, but there is no standard integration fee or standard statement line for the work itself.

Your integration choice also affects payment-data exposure and compliance work. Hosted pages and embedded fields reduce the card data your systems handle, but do not remove every PCI DSS responsibility. PCI DSS v4.0.1 is the current version as of 2026, and the future-dated requirements of v4.0 became mandatory on March 31, 2025. A direct API integration that handles card data puts more of your environment in scope.

What you can actually change

Choose an integration that fits your checkout and technical resources, then test payment outcomes before launch. The goal is to prevent mismatched orders, duplicate updates, and avoidable maintenance, while knowing which systems handle card data.

• Compare hosted checkout, embedded fields, plugins, and API options for checkout control and the card data your systems handle.
• Test approvals, declines, cancellations, timeouts, refunds, delayed notifications, and duplicate notifications before launch.
• Match payment and settlement records to order IDs, and verify status updates before changing an order to paid.
• Protect API credentials with server-side handling and document which party is responsible for each PCI DSS task.

1. 01
   Map the payment flow. Write down which system collects payment details, sends requests, receives status updates, and records refunds.
2. 02
   Test failure cases. Run test transactions for timeouts, duplicate notifications, declines, and refunds before accepting live payments.
3. 03
   Review data handling. Confirm which parts of your website or app handle card data and document the related PCI DSS responsibilities.

Frequently asked questions