<p>Architected end-to-end PSP integrations for Stripe and Mollie, covering merchant onboarding, payment flows, and webhook reconciliation within a microservices aggregator, enabling millions of pounds in monthly transactions across 500+ businesses.</p><p> Engineered a high-throughput payout generation system on Stripe Connect with batched processing and multi-tier fee calculation for hundreds of merchants.</p><p> Introduced Redis caching to reduce payout lookup latency by 35% and improve throughput at peak load.</p><p> Integrated PayByLink via Adyen and designed a subscription recovery system with automated email alerts, configurable grace periods, and expiry notifications, reducing involuntary SaaS churn.</p><p> Built the Kayana Loyalty Programme from scratch, including points accrual and redemption, tier management, and programme configuration.</p><p> Engineered a full-scale marketing automation platform sending bulk email, SMS, and push notifications to 50,000+ customers, with integrated delivery, open, and click tracking for data-driven campaign optimisation.</p><p> Developed and maintained backend microservices on AWS ECS/EKS supporting self-service kiosks, EPOS, mobile apps, and QR code ordering, contributing to a 15% increase in transaction volume.</p><p> Integrated the Nash delivery platform via webhooks, automating real-time delivery tracking and improving fulfilment efficiency by 20%.</p><p> Implemented OpenAPI/Swagger-documented search that cut order processing time by 20%.</p><p> Led migration of the core backend from Java 14 to Java 24 with GraalVM, achieving ~25% faster startup times across all production microservices.</p><p> Implemented MFA across multiple AWS Cognito user pools securing 5,000+ users.</p><p> Managed AWS deployments across EC2, S3, RDS, Lambda, CloudWatch, Route53, and Load Balancer for high availability and observability.</p><p> Built AI-powered customer support chatbots using LangChain and Ollama, integrated with MCP servers for context-aware responses.</p><p> Led code reviews and enforced distributed systems best practices across a team of 6 engineers.</p><p> Mentored 2 junior developers on performance tuning, clean architecture, and TDD, reducing production incidents by 30%.</p>
