Cross-Border PayTech (Madrid)
16 Weeks (Core Refactoring)
Node.js Microservices, Redis, Next
PSD2 / Mutua Assured
The client was processing cross-border SEPA transactions for 3,400+ European merchants using a monolithic PHP backend. During peak European shopping hours, concurrent API webhook requests caused MySQL database table deadlocks, triggering a catastrophic 4.2% transaction timeout rate. Merchants were experiencing 48-hour delays in automated settlement reconciliation, leading to massive enterprise churn and imminent PSD2 compliance warnings.
We decoupled their payment gateway into an asynchronous, event-driven Node.js (TypeScript) microservice architecture. Using Redis Pub/Sub as an in-memory queue, transactions are now validated and written to an idempotent double-entry ledger in just 12 milliseconds. We engineered an ultra-slick, real-time React analytics dashboard for merchants featuring instant webhook retries and zero-knowledge encrypted API keys.
Down from 1,400ms monolithic lock
Handled with zero dropped frames
Auto-scaling Docker Swarm nodes
Mathematically absolute ledger sync
Every incoming SEPA/SWIFT payload generates a unique hash key. Network retries or duplicate webhook firings are mathematically caught and ignored instantly.
Native integration with European Open Banking APIs (Tink/TrueLayer), implementing strict Strong Customer Authentication (SCA) biometric flows.
Merchant CFOs can visualize live multi-currency float, real-time rolling reserves, and automated SEPA Instant payout thresholds via custom WebSockets.