Guide to payment gateway integrations: How to get started (2026)

Key takeaways:

• Payment gateway integrations connect your website, app, or point-of-sale system to the infrastructure that processes customer payments.

• The right integration method (whether it’s an API, hosted page, plugin, or payment link) affects your checkout experience, security obligations, and ongoing costs.

• Airwallex lets Singapore businesses accept payments across multiple integration types, with support for local payment methods like PayNow and GrabPay, and like-for-like settlement to avoid unnecessary foreign exchange fees.

Payment gateway integrations are how businesses connect their checkout to the technology that captures, encrypts, and processes customer payments.

Whether you run an eCommerce store, a subscription service, or a marketplace, the integration method you choose shapes everything from conversion rates to compliance obligations.

Below, we cover everything you need to know about integrating with a payment gateway: how it works, the different integration types, what to look for, and how to get started.

What is a payment gateway integration?

Payment gateway integration is the process of connecting your business's website, app, or point-of-sale (POS) system to a payment processor. Think of it as the bridge between your customer's bank and your business.

A payment gateway securely transfers a customer's payment details to the processor while protecting sensitive financial information like card data. It acts as the intermediary between the customer's bank and the merchant, ensuring safe and efficient payment processing.

For businesses, integrating with a reliable payment gateway ensures the payment process is efficient, secure, and capable of handling diverse payment methods.

Shoppers increasingly expect a smooth checkout experience, and when you deliver one, you're more likely to build trust and drive conversions.

How payment gateway integration works

Understanding what happens behind the scenes helps you make better decisions about which integration type suits your business. Here’s what happens every time a customer pays:

• The customer enters payment details. Card data is entered into the checkout form, or a stored credential like Apple Pay or Google Pay is selected.

• The gateway encrypts and routes the data. The gateway captures the payment information, encrypts it, and transmits it to the payment processor.

• The processor requests authorisation. The processor forwards the request through the relevant card network — Visa, Mastercard, and so on — to the customer's issuing bank, which checks available funds, fraud signals, and account status.

• The bank returns an approval or decline. The response travels back through the network to your checkout, typically in under two seconds.

• The order is confirmed or the customer is prompted to retry. An approved response triggers the order confirmation. A decline surfaces an error, giving the customer the option to use a different payment method.

• Funds are settled. Authorised transactions batch and settle to your account, usually within one to five business days depending on your provider and currency.

6 benefits of payment gateway integrations

The right payment gateway affects your conversion rates, costs, and ability to grow. The provider and method you choose will shape the customer experience at one of the most critical points in the buying journey.

Here is what a well-chosen payment gateway integration gives your business:

• Local payment method support. Accept PayNow, GrabPay, and ShopeePay alongside cards, so Singapore customers can pay the way they already do.

• Lower cart abandonment. Customers who don't see their preferred payment method at checkout are likely to leave — offering the right options keeps them there.

• Reduced FX costs. Settle in the same currency your customers pay in, so funds aren't automatically converted and you avoid unnecessary foreign exchange fees.

• Regulatory compliance. Choose a provider licensed by the Monetary Authority of Singapore (MAS) and compliant with the Personal Data Protection Act (PDPA) to meet local requirements.

• Built-in fraud protection. PCI DSS compliance, 3D Secure (3DS) authentication, and AI-powered fraud detection protect your business and your customers.

• Room to scale. The right gateway supports higher transaction volumes, multiple currencies, and new markets without requiring you to rebuild your payment setup.

5 types of payment gateway integrations

There are several ways to connect a payment gateway to your business. Here’s a quick overview:

The right method depends on how much control you want over the checkout experience, how much developer resource you have, and what your Payment Card Industry Data Security Standard (PCI DSS) compliance obligations look like.

1. API integration

API integration connects your platform directly to the payment gateway provider's Application Programming Interface (API), giving you complete control over the payment flow and checkout design. You can build fully custom experiences, support recurring payments, handle multi-currency transactions, and store payment details securely via tokenisation.

The trade-off is complexity. API integrations require dedicated developer resources to build and maintain, and because card data passes through your environment, your business takes on the highest level of PCI DSS compliance scope.

Airwallex offers a Payments API for businesses that want complete control over their checkout experience and payment workflows.

2. Hosted payment pages

A hosted payment page redirects customers to a secure, third-party checkout page managed by the gateway provider. The provider handles security and PCI DSS compliance on your behalf, which reduces the burden on your team.

The downside is less control over the checkout experience. Because customers leave your site to complete payment, some may hesitate, and that redirect creates a drop-off point that can affect conversion rates.

Airwallex offers a pre-built hosted payment page that lets businesses start accepting payments quickly while keeping PCI DSS compliance requirements low.

3. Embedded iframes and hosted fields

This method sits between hosted pages and full API integration. Payment fields appear within your checkout page but are served inside an iframe or as hosted fields directly by the gateway.

From the customer's perspective, they never leave your site. From a compliance perspective, card data still doesn't touch your servers, which keeps your PCI DSS scope low, similar to a hosted page.

This is a good option for businesses that want an on-site checkout experience without taking on the full compliance burden of a direct API integration.

4. Plugins and extensions

Plugins provide ready-to-use payment integrations for eCommerce platforms like Shopify, WooCommerce, and Magento. They require minimal setup and no custom development, making them a practical choice for businesses that want to get up and running quickly.

The limitation is customisation; you work within what the plugin supports.

Airwallex offers payment plugins for major eCommerce platforms, letting you connect without writing any code.

5. Payment links

Payment links are shareable links that take customers to a secure checkout page, no website or integration required. You generate a link and send it via email, SMS, or social media.

This works well for service-based businesses, freelancers, and anyone handling one-time or ad hoc transactions.

Airwallex offers payment links that let businesses accept secure online payments with no fuss.

6 key factors when choosing a payment integration solution

With several integration types and providers available, the right choice comes down to your business model, technical capacity, and the markets you serve. Here are the factors worth weighing before you decide:

1. Payment methods and currency support

Customers want to pay their way. In Singapore, that means supporting PayNow, GrabPay, and major card networks as a baseline.

If you sell internationally, check whether the gateway supports preferred methods in your target markets: Alipay and WeChat Pay for China, iDEAL for the Netherlands, and so on.

Also look at currency settlement. Accepting payments in multiple currencies is standard; what matters more is whether you can settle in those currencies without automatic conversion. Like-for-like settlement lets you hold funds in the currency they arrived in and avoid unnecessary FX fees.

You can read more about how payment gateway fees work in our dedicated guide.

2. Security, compliance, and fraud prevention

Choose a gateway that is PCI DSS compliant and includes fraud detection, encryption, and 3DS authentication. In Singapore, also confirm the provider is licensed by the MAS as a Major Payment Institution, and that it handles customer data in line with the PDPA.

Advanced fraud tools (such as AI-powered risk scoring and real-time transaction monitoring) help block fraudulent transactions without generating false declines that frustrate legitimate customers.

3. Integration and technical compatibility

Your payment solution needs to fit your existing tech stack. Ask whether it offers API-first flexibility for custom setups, or plug-and-play options for your eCommerce platform.

Check compatibility with your accounting software, Enterprise Resource Planning (ERP) tools, and Customer Relationship Management (CRM) systems.

Also consider your team's capacity. A fully managed hosted solution may save time and resources if you don't have developers available for a direct integration.

4. Cost and total cost of ownership

Look beyond the transaction fee. Setup costs, maintenance, chargeback fees, and currency conversion charges all contribute to what you actually pay. A gateway with a lower headline rate but high FX conversion costs can end up more expensive than one with transparent, flat pricing.

Look for competitive FX rates, automated reconciliation, and real-time transaction reporting to keep costs predictable.

5. Scalability for growth

If expanding into new markets is part of your plan, your gateway should support it without a full rebuild. Look for multi-currency accounts, local acquiring in key markets, and regulatory compliance across the regions you want to enter.

For a closer look at how cross-border payments work, see our dedicated guide.

6. Business model fit

Consider your transaction volumes, average order values, and whether you need features like recurring billing, split payments, or usage-based billing.

A gateway that works for a one-person consultancy looks very different from one built for a high-volume marketplace. Choose one that matches where your business is now and where it is headed.

Step-by-step guide to payment gateway integration

Payment integration doesn't have to be complicated. Here is how to go from choosing a provider to accepting live transactions:

Step 1: Choose your integration method and provider

Start by mapping the payment methods your customers expect, the platforms you already use, and your team's technical capacity.

Use these to narrow down the integration type, then evaluate providers against security, global reach, supported currencies, and pricing. Comparing providers side by side will help you find the best fit.

Step 2: Set up a merchant account

A merchant account is required to process card payments. Setup typically requires business details, financial documentation, and bank account information.

Some providers, like Airwallex, bundle merchant account functionality into their business accounts, so you can settle, hold, and transfer funds without opening a separate account.

Step 3: Obtain API keys or integration credentials

Once your account is approved, you'll receive API keys or credentials that connect your system to the gateway. Treat these like passwords: store them securely and restrict access to prevent unauthorised use.

Step 4: Integrate the gateway with your platform

Connect the gateway using the method that suits your setup. For full control, use the API. For a faster start, use a hosted page or iframe. For eCommerce platforms like Shopify or WooCommerce, install the relevant plugin.

Step 5: Configure fraud rules and authentication

Before going live, set your fraud detection thresholds, enable 3DS where required, and configure retry logic for soft declines.

Well-configured fraud rules block suspicious transactions without rejecting legitimate ones: getting this balance right protects both revenue and customer trust.

Step 6: Test the integration thoroughly

Use a sandbox environment to simulate transactions before accepting real payments. Test authorisations, declines, refunds, expired cards, and currency conversion scenarios.

Confirm that payment events feed correctly into your reporting and that order data maps accurately to your reconciliation workflow.

Step 7: Go live and monitor closely

Once testing is complete, deploy to production. Watch authorisation rates, decline rates, and error logs carefully during the first 24 to 48 hours of live traffic.

Investigate any unexpected drops in authorisation rates immediately: they often point to misconfigured fraud rules or integration issues that are easier to fix early.

Simplify payment gateway integration with Airwallex

The best payment gateway integration doesn't just help you accept payments. It helps you lower costs, improve checkout conversion, and scale into new markets without rebuilding your payment infrastructure.

With Airwallex, you can:

• Accept payments your customers already use, including cards, PayNow, GrabPay, and 160+ payment methods across 180+ countries.

• Reduce unnecessary FX costs with like-for-like settlement, so you can settle funds in the same currency your customers pay in.

• Support global growth with multi-currency accounts, local acquiring, and a single platform for domestic and international payments.

• Choose the integration that fits your business, whether that's a fully custom API, hosted checkout, no-code plugin, or payment links.

• Protect revenue with built-in fraud detection and intelligent 3D Secure authentication that helps maximise payment acceptance rates.

Frequently asked questions (FAQs)

What is the difference between a payment gateway and a payment processor?

A payment gateway captures and encrypts payment data at checkout and routes it to the payment processor. The processor then handles the transaction itself, communicating between the card network and the customer's bank to get an approval or decline. Some providers bundle both functions together; others keep them separate.

What is the easiest way to integrate a payment gateway?

The easiest integration method depends on your setup. If you run an eCommerce store on Shopify, WooCommerce, or Magento, a plugin is usually the fastest path: there’s no coding required. If you don't have a website at all, payment links let you accept payments with no integration work whatsoever.

Do I still need PCI DSS compliance if I use a third-party gateway?

Yes, using a third-party gateway reduces your compliance obligations but doesn't remove them entirely. Hosted pages and iframe integrations keep your PCI DSS scope low because card data never touches your servers. API integrations put more of your environment in scope and require more rigorous compliance work.

Which integration type is best for international selling?

API integration gives you the most flexibility for international selling: you can customise the checkout experience by market, support local payment methods, and handle multi-currency transactions. That said, the right answer depends on your resources. A plugin or hosted page with strong international payment method support can also work well if developer capacity is limited.

How does payment gateway integration affect conversion rates?

The integration type directly affects how smooth the checkout experience feels. Hosted pages that redirect customers off-site can cause drop-off. On-site methods like iframes and API integrations keep the experience within your brand. Beyond that, offering the right payment methods matters: research shows that a one-second delay in page load time alone can reduce conversions by up to 7%.¹ A well-integrated gateway minimises friction at every step.

What should Singapore businesses look for in a payment gateway?

Look for MAS licensing, PDPA-compliant data handling, and support for local payment methods like PayNow and GrabPay. Beyond compliance, prioritise transparent pricing, like-for-like currency settlement if you sell internationally, and an integration method that fits your technical capacity. Airwallex meets all of these criteria and supports both local and cross-border payments from a single account.

Sources

1. https://www.bigcommerce.com/glossary/page-load/