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Payment Infrastructure

Payment Gateway

Secure acceptance for every channel

Presentation

Overview

The payment gateway sits between checkout and the wider payments ecosystem, translating a single integration into acceptance across acquirers, card schemes and alternative payment methods. Pay Engineers builds gateways designed for conversion and compliance in equal measure: every authentication step, routing decision and token exchange is engineered to reduce friction for legitimate transactions while enforcing the security rules that schemes, regulators and issuers require.

Rather than assembling a checkout from disconnected SDKs and hoping they behave consistently under load, you get a coherent gateway layer that developers integrate against once and rely on for years, with authentication flows, tokenisation and routing logic that evolve as scheme mandates and market conditions change.

Because the gateway is engineered specifically for your acquiring relationships and market mix rather than adapted from a generic template, it can encode business rules that a shared, multi-tenant platform simply cannot expose to you as configuration options.

Who This Is For

  • E-commerce platforms and merchants needing a resilient, compliant checkout across multiple markets and currencies
  • PSPs and ISOs building acceptance infrastructure for their own merchant base
  • Subscription and marketplace businesses that need robust tokenisation and recurring authorisation support
  • Any business currently dependent on a single acquirer connection with no failover or routing flexibility

We frequently work with businesses that have outgrown a plug-and-play gateway but are not yet ready for a full custom processor build. This service is deliberately scoped to sit at that stage: independent enough to give you control, focused enough to ship in months rather than years.

What You Get

  • Hosted and API-based checkout options so you can match your UX ambitions to your PCI scope requirements
  • 3-D Secure 2 and SCA orchestration tuned to minimise unnecessary challenge flows and protect conversion
  • A token vault that removes raw card data from your systems while preserving recurring billing capability
  • A webhook event bus giving your systems real-time visibility of authorisations, captures, refunds and disputes
  • A sandbox environment and hands-on support through acquirer and scheme certification

Technical Approach

The gateway is built on Laravel and Node.js services behind a PostgreSQL system of record, with Redis handling session state, rate limiting and idempotency guarantees for API calls. A dedicated 3DS Server component manages authentication challenges and exemption logic, so that low-risk transactions can be routed through frictionless flows wherever scheme and issuer rules allow it.

Smart routing logic evaluates acquirer health, cost and approval rates in real time, failing traffic over to alternative rails the moment a connection degrades. Tokenisation follows network token and gateway token standards so that stored credentials remain usable even across acquirer changes, protecting your recurring revenue from the operational risk of a single point of failure. Webhooks are signed and retried with exponential backoff so downstream systems can trust every event they receive.

Delivery Process

  • Discovery workshops to map your current checkout, acquirer relationships and payment method mix
  • Integration architecture and API contract design agreed jointly with your engineering team
  • Sprint-based build with sandbox access from an early stage so your team can integrate in parallel
  • Certification support with acquirers, schemes and 3DS providers to remove go-live blockers
  • Phased production rollout with monitoring dashboards and a defined hypercare window

Outcomes and Benefits

  • Higher authorisation rates through intelligent routing and carefully tuned authentication flows
  • Reduced PCI scope thanks to tokenisation and hosted field options
  • Resilience against acquirer outages through automatic failover between rails
  • A gateway your engineering team can extend as new payment methods, markets and acquirers are added over time

Technologies

Laravel Node.js PostgreSQL Redis 3DS Server

FAQ

The gateway is built as an acquirer-agnostic layer that can connect to multiple acquirers and card schemes in parallel, plus regional methods such as bank transfers, wallets or buy-now-pay-later where relevant to your markets. We scope the exact method list with you during discovery based on your target geographies and existing acquiring relationships, and design the routing layer so new methods can be added later without rebuilding checkout integrations. If you already have acquirer contracts in place, we integrate against those rather than forcing a change of processing relationship. This keeps the gateway useful even as your acquiring mix evolves over time.
Strong Customer Authentication and 3-D Secure v2 orchestration are built into the authorisation flow by default, including exemption logic for low-risk, low-value or trusted-beneficiary transactions where scheme and regulatory rules permit it. We implement this so legitimate transactions are not needlessly challenged, since over-triggering SCA is one of the most common causes of lost conversion in European checkouts. The flow is kept current with evolving PSD2 regulatory technical standards and scheme mandates, and we document the authentication decisioning logic so your compliance team can review it independently. Exemption thresholds remain configurable so you can tune risk appetite without a code change.
A typical gateway build and first-acquirer integration takes 3 to 5 months, covering checkout SDKs, tokenisation, webhook infrastructure and a basic transaction back office. Timeline depends heavily on the number of acquirers and payment methods in scope and whether you need PCI DSS SAQ A or SAQ A-EP level tokenised integration versus a more involved server-side flow. We deliver in phases so you can go live with a core method set first and add further acquirers or methods in subsequent releases without downtime. Certification testing windows with acquirers are built into the plan from the outset rather than treated as an afterthought.
The gateway is designed with a routing abstraction layer specifically so new acquirers, schemes or local payment methods can be added as connectors without changes to your checkout integration or client applications. This lets you renegotiate acquiring relationships, add smart routing for cost or approval-rate optimisation, or expand into new markets without a re-platforming project. We document the connector interface so your own engineers, or another vendor, can add methods independently once the initial build is complete. This avoids the vendor lock-in that comes with monolithic gateway integrations.
The gateway exposes signed, idempotent webhooks for every transaction lifecycle event, alongside a REST API for querying transaction, refund and dispute status on demand, so your systems never rely on webhooks alone for state. We build retry and dead-letter handling into the webhook delivery so temporary outages on your side do not result in silently lost events. Where you need reconciliation against acquirer settlement files, we align the transaction identifiers and reporting periods so matching is straightforward rather than a manual spreadsheet exercise. All of this is documented in an OpenAPI specification delivered as part of the engagement.
Launch includes a stabilisation period with monitoring dashboards for authorisation rates, latency and error codes, so issues are caught before they affect a meaningful share of transactions. We provide defined incident response support during this window and hand over alerting thresholds and runbooks to your operations team. After the included period, you can move to an SLA-backed managed support retainer covering scheme mandate changes, new method additions and performance tuning, or take ownership of ongoing maintenance in-house using the documentation we provide. Either path is designed to avoid the gateway becoming unmaintainable once the original build team moves on.

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