Building a payment gateway is no longer reserved for large, global payment service providers. Increasingly, the market is expanding. Now, new players, such as licensed banks, electronic money institutions (EMIs), and payment service providers (PSPs), are choosing to offer their own payment services. For some, this is a natural extension of an existing financial product suite. For others, it becomes the foundation of a new payments business.
At first glance, processing payments may appear straightforward. In practice, a gateway sits at the intersection of regulation, technology, operations, and user experience. Success depends less on individual features and more on how these elements work together end-to-end. Building something that merchants trust, regulators approve, and operations teams can scale requires careful design choices from the very beginning.
This article takes a practical look at what it takes to build a payment gateway as a card acquirer, with a focus on enabling merchants to get live quickly and supporting real-world payment flows over time, whether you serve merchants directly or support PSPs and platforms that do. In the sections that follow, we break down the key decisions and building blocks involved, from onboarding and integration to core gateway capabilities, risk management, and day-to-day operations.
The journey starts long before the first transaction is processed. How you expand your payment services is shaped by your existing business model. Some organisations favour a product-led approach, allowing merchants to self-serve through digital interfaces. Others rely on a sales-led strategy supported by account managers and technical specialists. Many successful acquirers combine both.
Once a merchant agrees to work with you, onboarding begins. This stage blends regulatory obligations with operational execution and is often where friction first appears. Onboarding typically includes ‘know your customer’ (KYC) and ‘know your business’ (KYB) checks, alongside anti-money laundering (AML) screening. For banks and EMIs with existing customer relationships, much of this information may already be available. For some, it often requires integrating dedicated KYC and AML providers that support the relevant markets.
Automation can handle most cases, but exceptions are inevitable. Merchants may submit incomplete information or require manual review. Designing onboarding flows that handle these exceptions efficiently is critical to maintaining momentum and delivering a strong first experience.
Once approved, merchants must be configured and integrated. This includes registering them with card schemes, such as Visa and Mastercard, assigning the correct identifiers, and enabling wallets like Apple Pay and Google Pay. Early-stage operations may rely on manual processes, but this quickly becomes a bottleneck as volumes grow. Reusing onboarding data to automate configuration reduces errors and shortens go-live times.
Merchants then need to integrate your gateway into their checkout or payment flows. For online use cases, this typically means supporting multiple integration options, such as hosted payment pages, web-based SDKs, mobile SDKs, and direct API integrations for PCI-certified environments. Each option serves merchants with different technical capabilities and expectations.
Across all integration models, sensitive card data must be handled securely and replaced with tokens. Tokenisation ensures compliance while enabling subscriptions, saved cards, and recurring payments. From a merchant’s perspective, clear documentation and reliable integration tools often matter as much as the API itself.
Every payment gateway must support the full payment lifecycle. This begins with securely collecting payment details across channels, including traditional card entry and digital wallets. Card data must be tokenised so merchants never handle raw details, supporting both compliance and repeat usage.
During authorisation, the gateway connects to the processor and card schemes in real time to confirm funds availability. Support for transaction types, such as subscriptions and merchant-initiated payments, is essential for many business models. Network tokenisation increasingly plays a role in improving approval rates and reducing fraud, particularly for stored-card use cases.
Authentication has become a central part of the flow. Gateways must support 3D Secure, and handle mandates, exemptions, and risk-based authentication decisions. The challenge is balancing regulatory compliance with conversion, as unnecessary friction can lead to shopper drop-off.
Risk is inherent in card acquiring. When merchants fail to deliver goods or services, acquirers often carry the financial exposure. As a result, gateways commonly integrate specialised fraud and risk providers to analyse transaction context, shopper behaviour, and device data in real time.
These checks must be orchestrated seamlessly within the payment flow. Overly aggressive controls can harm conversion, while insufficient controls increase exposure. Finding the right balance is essential.
Operational tooling is equally important. Acquirers need internal interfaces to configure merchants, monitor performance, and investigate issues. Merchants need self-serve portals to manage integrations, handle refunds and enquiries, and access reporting. Clear, up-to-date documentation underpins all of this, reducing support effort and improving the overall experience.
Building a payment gateway is not just a technical exercise. It is a product, regulatory, and operational challenge that requires careful design choices and a deep understanding of merchant needs. When executed well, a gateway becomes a scalable foundation that supports growth, manages risk, and adapts as payment expectations evolve.
For many acquirers, partnering with a platform that abstracts part of this complexity can significantly reduce time-to-market and operational burden. At XPP, we see growing demand for approaches that allow providers to move quickly without giving up control over merchant relationships or long-term strategy. Modernised payment solutions, such as Ginger, with direct access to a payment processor like Silverflow, are designed with this balance in mind, sitting on top of acquiring infrastructure while handling much of the gateway complexity.
Ultimately, whether you choose to build, buy, or combine approaches, the most important decision is selecting a path that aligns with your ambitions and the merchants you aim to serve.
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