Payment gateway integration for reliable transactions

We work provider-agnostic. Our teams have shipped integrations with the major European processors (Adyen, Worldline, Stripe, Mollie) as well as regional acquirers and bank-direct SEPA rails. More important than any single logo is the architecture: we place an orchestration layer between your platform and the PSP, so every provider is reduced to the same internal contract for authorization, capture, refund and webhook events. Your product code never talks to a PSP SDK directly. That single decision is what later allows you to add a second provider for a new market, negotiate better acquiring fees with real switching power, and survive a provider incident by rerouting traffic. During selection we benchmark candidate PSPs against your actual transaction mix (card versus SEPA share, average ticket, recurring ratio, dispute rate) rather than against feature checklists, because pricing and authorization performance vary heavily by segment.

The goal is for raw card data to never touch infrastructure you operate. We integrate hosted payment fields or PSP-side tokenization so the primary account number flows directly from the customer's browser to the provider, and your platform only stores opaque tokens. Done correctly, this moves most merchants from a heavy SAQ-D assessment toward SAQ-A or SAQ-A-EP, cutting audit effort dramatically. Where business requirements genuinely need card references shared across providers, we introduce network tokens or an independent vaulting service, so tokens stay portable instead of locking you to one PSP. We also review the less obvious leak paths: card numbers landing in logs, in support tickets, in analytics events or in database backups, because that is where assessments usually fail. The result is a documented cardholder-data flow your QSA can sign off on, with the compliance boundary drawn as tightly as possible around third parties rather than around your platform.

Yes, provided the integration is structured for it, and that is exactly what our orchestration layer is for. We normalize each provider behind one internal API covering authorization, capture, refund, mandate management and webhooks, so adding a PSP becomes an adapter project instead of a checkout rewrite. The genuinely hard part is usually the stored credentials: tokens created by one provider cannot be replayed at another. We handle that with network tokenization where card schemes support it, with provider token-migration programs, or with a progressive re-tokenization flow that converts customers at their next successful payment. Routing rules then decide which provider sees which transaction: by country, by card scheme, by cost, or dynamically by recent authorization rates. Most clients run the new PSP in shadow mode first, processing a small share of live traffic while both reconciliation outputs are compared, before any meaningful volume is shifted.

Duplicate charges are an architecture problem, and we design them out at three levels. First, every payment attempt carries an idempotency key derived from your business operation, so a retried request after a timeout returns the original result instead of creating a second charge. Second, each payment lives in an explicit state machine with persisted transitions; a process that crashes mid-capture resumes from the recorded state rather than starting over. Third, we treat the PSP's webhook stream and our own records as two sources that must reconcile: a recovery job continuously compares them, detects attempts that succeeded at the provider but were never confirmed on our side, and resolves them automatically. During PSP outages, requests queue with store-and-forward semantics and replay under the same keys once the provider recovers. Transaction monitoring then alerts on anomalies such as authorization-rate drops and webhook lag before customers notice anything.