How payment gateways integrate with eCommerce platforms

Why payment gateway integration is important

When you set up a payment gateway for your online store, it can influence how quickly and smoothly customers can complete their purchases. A well-integrated payment gateway enables fast, seamless transactions, helping customers receive their products or services sooner and ensuring your business gets paid without delay. An improperly configured gateway may lead to failed transactions, customer frustration and more work for you as you troubleshoot payment errors or chase up missing funds.

If your payment gateway isn’t integrated effectively, your customers may be unable to complete their purchase. This interruption often causes shoppers to abandon their cart altogether, resulting in lost revenue.

Understanding how your payment gateway connects to your eCommerce store empowers you to choose the right configuration for your business. Ensuring seamless integration helps set your business up for long-term success and a streamlined customer experience.

Common ways payment gateways integrate with eCommerce platforms

What payment integration means for an online store

A well-integrated payment gateway serves as a secure, reliable bridge between your online store and major card networks, ensuring transactions are processed safely and efficiently.

How a payment gateway connects an online store to card networks

At NAB, our payment gateway is designed to connect your online store directly with major card networks such as Visa, Mastercard and American Express. When a customer makes a purchase, the gateway securely sends their payment information to the appropriate card network for authentication. This connection ensures payments are authenticated quickly and processed with confidence, giving both you and your customers peace of mind.

The role of the gateway at checkout and during payment authorisation

As soon as a customer enters their card details, the payment gateway encrypts and transmits the information securely for authorisation. It checks with the card issuer to confirm funds are available and that the transaction is legitimate. Once approved, the gateway completes the transaction and notifies your store so you can fulfil the order.

What’s handled by the platform versus the gateway

Your eCommerce platform (such as Shopify or WooCommerce) manages your product listings, the shopping experience and overall order management. The payment gateway, however, processes card payments, protects sensitive data and ensures compliance with standards like PCI DSS. Integrating NAB Gateway brings together a smooth online shopping experience with secure, trusted payment processing allowing you to focus on growing your business.

How payment gateways connect to eCommerce platforms

Payment gateways connect to eCommerce platforms using different integration methods, each designed to streamline checkout and ensure secure, efficient online payments. Your ideal method depends on your technical resources, platform and long-term business goals.

Pre-built integrations offered by eCommerce platforms

Most leading eCommerce platforms provide pre‑built integrations for a wide range of payment gateways through partnerships. These integrations are developed and maintained by the platform, allowing merchants to activate a payment gateway directly within their store settings. With only a few configuration steps you can start accepting payments quickly, making this approach ideal for businesses wanting fast, low‑effort implementation.

Plugin-based integrations

eCommerce platforms commonly support payment plugins or extensions that can be enabled with minimal configuration. These plugins simplify the integration process by handling most of the technical requirements for you. They’re easy to install, require little development knowledge and receive ongoing updates from the platform or plugin provider, making them ideal for rapid deployment and straightforward maintenance.

API integrations

Businesses needing more customisations can integrate via Application Programming Interface (API). API-based integration allows developers to create tailored checkout experiences, support advanced features and design highly customised workflows. While more technical, API integration offers maximum control and branding potential.

What businesses typically need to configure during setup

Regardless of integration method, key setup steps usually include:

• Gateway account setup: Create an account and retrieve credentials (API keys or merchant IDs).
• Platform configuration: Enter credentials into your platform’s payment settings, linking your store with the payment processor.
• Security settings: Enable SSL certificates, fraud protection tools and PCI DSS compliance to protect sensitive payment information.
• Payment options: Choose which payment types to accept (e.g. credit and debit cards, digital wallets).
• Testing and verification: Run test transactions to ensure everything functions smoothly and payments are processed correctly.

These steps help businesses achieve a secure, reliable and customer-friendly integration.

eCommerce platforms supported by NAB Gateway

NAB Gateway supports integration with widely used eCommerce platforms, helping businesses connect their online checkout with their secure payment gateway.

• Shopify – NAB Gateway integrates seamlessly with Shopify using an easy-to-install plugin. Merchants enjoy a quick setup, secure card payment processing and customisable payment options within the Shopify dashboard. Transaction history, refunds and payment settings can all be managed effortlessly through the Shopify platform.
• WooCommerce – NAB Gateway is compatible with WooCommerce, ideal for WordPress-based stores. Integration can be achieved using official plugins or custom API connections. WooCommerce offers extensive flexibility, enabling secure payments, automated payment confirmations, status updates and custom workflows.
• Magento – NAB Gateway supports Magento, a platform popular with larger or more complex online stores. Thanks to its advanced architecture, Magento allows deep customisation via API, enabling branded checkout experiences and advanced payment capabilities.
• BigCommerce – NAB Gateway integrates with BigCommerce through user-friendly plugins, making it easy to configure payment options, review reporting tools and automate post-payment processes inside the platform.

What the checkout flow looks like once integrated

Customer completes checkout on the eCommerce platform

After selecting products, customers proceed to checkout, enter their billing and shipping details and choose a payment method. Platforms like Shopify, WooCommerce, Magento and BigCommerce guide customers through a clear, secure checkout experience.

Payment details are securely passed to the gateway

Once submitted, the platform encrypts and sends payment details to the integrated payment gateway. The gateway processes sensitive information securely and ensures compliance with industry standards like PCI DSS to protect sensitive data. This step ensures that payment details remain confidential and reduces the risk of fraud or unauthorised access.

Transaction is approved or declined

The gateway contacts the customer’s card issuer to approve or decline the payment. Approved payments are transferred and confirmed; declined payments prompt customers to retry. Note: Settlement times may vary based on processing arrangements and the customer’s card issuer. This real-time feedback can help reduce cart abandonment and can improve the overall shopping experience.

Managing payments after checkout

How payment confirmations flow back into the platform

After approval, the gateway sends confirmation back to the platform in real time, updating the order status and displaying results to both the merchant and customer. The platform will typically change the order status in the merchant dashboard to “paid” or “processing.” For declined payments, customers are notified instantly and are prompted to retry payment or resolve any input issues. This automated communication between the payment gateway and the platform helps to reduce manual intervention and streamlines order management.

Where transaction records appear

Transaction records are stored within the backend of your eCommerce platform and can be easily accessed through the merchant dashboard. Each order includes key payment details such as the payment method, transaction ID, timestamp and approval status so you have a clear view of every payment. Merchants can use these records to manage accounting, monitor sales performance and resolve any payment-related queries. Customers can also view their own transaction history through their account pages, including receipts, confirmations and order updates. This centralised approach keeps everything organised, transparent and straightforward for both customers and businesses.

How refunds are processed through the platform

Refunds are initiated directly from the merchant’s dashboard within the eCommerce platform. After selecting the relevant order, the merchant follows the platform’s steps to issue either a full or partial refund. The refund request is then securely passed to the payment gateway, which works with the customer’s card issuer or bank to return the funds. Once processed, the platform automatically updates the order status and adds the refund details to the transaction record. Customers are notified of the refund and can view the updated payment status in their account. This integrated process keeps refunds efficient, secure and straightforward, without the need for manual paperwork or separate systems.

When a custom integration might be needed

Custom-built stores or complex checkout flows

Businesses with custom platforms or specialised checkout journeys may need bespoke integrations to support custom interfaces, advanced cart logic or specialised payment options. Custom integration enables full control over the checkout process ensuring a seamless customer experience that aligns with the business’s needs.

Multi-store or multi-brand setups

Businesses running multiple online stores or brands may benefit from a custom integration that centralises payment processing and reporting across all storefronts. This creates a more streamlined operation, with unified transaction management, consistent customer experiences and simplified accounting. Payments from every store can be tracked and managed through a single backend system, making reconciliation faster and easier.

Higher transaction volumes

Businesses processing large volumes of transactions may need custom integrations. Standard solutions aren’t always built to handle heavy loads or offer advanced features like automated fraud checks or real‑time analytics. Custom integration lets businesses tailor their payment flows to manage spikes in demand, connect with ERP systems and strengthen security supporting efficient, reliable growth. What’s possible will depend on the platform, integration approach and services selected.