Senior Backend Engineer with 9+ years of experience building production systems using Node.js, TypeScript, and AWS. Deep expertise in e-commerce and retail, checkout, payment, inventory, and order management systems across serverless and containerized architectures.

Based in Istanbul. Open to work. Interested in backend-heavy products with real scale challenges — e-commerce, fintech, or anything where reliability actually matters.

🔗 ozersubasi.com · LinkedIn · X · [email protected]

Languages: Node.js TypeScript JavaScript Kotlin

Frameworks: Fastify Express NestJS Spring Boot

Cloud & Infra: AWS Lambda API Gateway DynamoDB S3 CloudWatch SNS SQS Docker Serverless

Databases: DynamoDB PostgreSQL MySQL MSSQL MongoDB Amazon Neptune Elasticsearch

Messaging & Caching: RabbitMQ Redis SNS SQS

APIs & Architecture: REST GraphQL Event-driven systems Microservices

Tools & Practices: Git CI/CD Agile/Scrum Grafana Payment integrations

Also exploring Flutter + Supabase for mobile.

• Senior Backend Engineer @ Retter.io (May 2024 — Jan 2026) — Built stock control and limit control systems for Unifree's 23 duty-free stores at Istanbul Grand Airport. Started building CarrefourSA's backend from scratch. Delivered backend for Wizzo using AWS Lambda, Amazon Neptune, and Elasticsearch.
• Senior Backend Engineer @ Yıldız Tech (Apr 2023 — Apr 2024) — Led real-time stock integration across platforms. Built checkout and payment services for CepteSok from the ground up with Kotlin, Spring Boot, and PostgreSQL.
• Senior Backend Engineer @ Istegelsin (Nov 2021 — Mar 2023) — Serverless e-commerce platform on AWS. Built GraphQL APIs supporting the full order lifecycle. Integrated Edenred meal card payments via Craftgate API.
• Backend Developer @ Faselis (Nov 2020 — Nov 2021) — Sole backend engineer. Designed serverless architecture on AWS Lambda with DynamoDB and MySQL.
• Backend Developer @ BiSU (Oct 2019 — Nov 2020) — Backend APIs for on-demand water delivery and grocery marketplace integrated with Istegelsin.

📄 Full resume →

• HookSense — Webhook inspection, debugging & testing tool. Catch, inspect, and replay webhooks in real-time via WebSocket. Modern alternative to webhook.site.
• Inboxical — Email testing API for developers. Create programmatic test inboxes, receive emails, extract verification codes in CI/CD pipelines. SDKs for Node.js, Playwright & Cypress.
• Cordy — Mobile reading app for my beloved wife (iOS & Android). Flutter, Supabase, Firebase. Full product lifecycle with CI/CD.
• yayinliyor.com — Serialized story platform. Next.js, TypeScript, Supabase, AWS S3. 1.5K+ readers, 218K+ reads.
• System Design Canvas — Visual system architecture tool. Drag-and-drop, templates, PNG/SVG/Mermaid export. 100% client-side.
• ContractLens — Runtime API contract validation middleware for Express. Catches breaking changes before your users do. Like Pact, but one line of middleware.
• Lambda Doctor — CLI that diagnoses AWS Lambda cold start issues. Static analysis with actionable fixes and estimated ms savings.
• Movie API — Fastify REST API with MongoDB, Redis caching, and Grafana/Loki observability stack.
• fastifyjs-supabase-auth — Fastify plugin for Supabase JWT authentication. Lightweight, type-safe, zero config.

🔗 All projects →

I write about backend architecture and AWS on Medium and my Blog.