Jan 2025 – Present · 1 yr 2 mos

• 1. Led architecture and delivery of core microservices for ShoppingCart, Order Tracker, Inventory, and Checkout Journey(Account/Login->IdVerification->Personal-Info->Shipping-> Appointment in case of broadband/routers ->Payments->order-review/consents->orderplace) in a multi-tenant B2C/B2B ecommerce platform serving 11 countries.
• 2. Directed a cross-functional team of 20+ engineers (backend, frontend, QA) to build and scale customer-facing Checkout journeys for fixed broadband, TV, landline, Mobile, and tariff products.
• 3. Owned platform stability and production readiness, driving infrastructure optimization, observability (Prometheus/Grafana/Metabase), and high availability for business-critical systems.
• 4. Expanded platform into Greece, Germany, and Croatia, leading end-to-end onboarding and achieving production go-live for both markets within 2 quarters through tight coordination with business and engineering teams.
• 5. Collaborated with central architecture and product teams to align system design with business goals, while delivering reusable libraries (e.g., cache control, auditing, authentication) to reduce engineering overhead.

Jan 2023 – Dec 2024 · 1 yr 11 mos

• 1. Contributed to building Oneshop, a customizable, multi-tenant e-commerce platform from scratch, enabling deployments across 5+ countries with CMS-driven tenant configurations.
• 2. Designed and developed core backend services such as Sales Catalog(NetflixConductor), ShoppingCart, Order Management, and Inventory.
• 3. Performed load testing and profiling for the DE (Germany) iPhone launch, optimizing listing page performance to handle peak traffic with <300ms response time under high concurrency.
• 4. Migrated Shopping DB from PostgreSQL to MongoDB with zero downtime and <0.3% production impact, achieving improved scalability and 2x faster read performance.
• 5. Implemented thread-level caching for critical APIs, reducing response latency by ~40% and lowering DB load during high-traffic periods.
• 6. Implemented Purge ShoppingCart database for carts older than 60 days using an open source library(https://jas34.github.io/scheduledwf/ and Netflix Conductor) with 0 downtime on production.

May 2021 – Dec 2022 · 1 yr 7 mos

• 1. Built core backend microservices such as ShoppingCart, Inventory, and Order Tracker using Java (Spring Boot), MongoDB, and Redis.
• 2. Developed a robust payment processing system from scratch, supporting Credit Card(BrainTree and MONRI), Wallet (PayPal), SEPA(Single Euro Payments Area), and IBAN-based payments, ensuring compliance with EU financial regulations and seamless checkout experience across regions.
• 3. Engineered key e-commerce systems, including a rule-based coupon engine, shipping service, and ID verification workflow for users onboarding and fraud prevention.
• 4. Implemented multibasket support in the ShoppingCart service, enabling customers to manage multiple concurrent purchases with tenant-specific configurations.
• 5. Implemented MM (Maintenance Mode) for the website, allowing seamless switchover and controlled downtime handling during platform updates and deployments.