Marek Lewandowski

Led a cross-functional squad (6–8 engineers, PM and designer) responsible for end-to-end design, delivery, and SLOs. Implemented Go microservices and Kotlin/Spring Boot services, Python tooling, and Node.js utilities deployed on Kubernetes (GKE/EKS) with Istio ingress, Argo CD/Helm GitOps, and Prometheus/Grafana dashboards. Built idempotent cart/checkout with token-scoped retries and consistent hashing; improved p95 latency and reduced auth errors. Orchestrated Kafka-based order pipeline (outbox/inbox, DLQ, replay tooling) to ensure exactly-once effects. Migrated legacy endpoints using Strangler Fig with canary/blue-green on Kubernetes; traffic controlled via Istio fault injections; change-failure rate <5% with weekly release cadence. Established observability via OpenTelemetry traces and RED/USE metrics; reduced MTTR and improved deployment reliability. Mentored three engineers and contributed to runbooks/post-mmortems.

Built internal enterprise systems used by 1,000+ wholesale partners, streamlining apparel distribution and partner operations. Developed full-stack platforms using React frontend, Next.js, Node.js (Express), and Python (FastAPI/Django) for warehouse management and partner operations. Migrated legacy .NET apps to React/Next.js, improving reliability and feature delivery speed. Architected microservices for order processing and inventory control on AWS ECS/Fargate, enabling auto-scaling and zero-downtime deployments. Implemented real-time inventory sync with Python, PostgreSQL, Redis, and AWS SNS/SQS; dashboards via New Relic and CloudWatch; MTTR reduced by ~45%. Built CI/CD pipelines (GitHub Actions) with Cypress/Jest/Pytest testing and Docker deployments; secured systems with JWT-based auth via AWS Cognito.

Developed responsive web components and scalable REST APIs for multiple clients. Implemented token-based session tracking and custom search indexing to improve data retrieval times. Built real-time chat features with WebSocket and integrated Stripe/PayPal into e-commerce flows. Participated in bi-weekly Agile sprints, authored unit tests and automated browser tests, and created onboarding documentation for junior engineers.