Özer Subaşı

Experience

Building and operating backend systems with Node.js, TypeScript, and AWS across production environments.

May 2024Jan 2026

Retter.io

Senior Backend Engineer

I work on backend systems for IGA Duty-Free’s Unifree platform across serverless and containerized architectures in production. I developed a purchase limit system using Node.js, TypeScript, and Fastify, integrating external MSSQL data and internal transaction flows backed by MongoDB. I implemented Redis caching and event processing via RabbitMQ to support asynchronous flows and maintain responsiveness. I also built a serverless stock tracking system on AWS Lambda to maintain per-store inventory state and update stock after purchases. Additionally, I contributed to backend features for Wizzo, using Amazon Neptune (graph data) and Elasticsearch for real-time/social use cases.

Node.jsAWSLambdaTypeScriptAmazon NeptuneFastifyMongoDBRedisRabbitMQMSSQLRancherKubernetes
Apr 2023Apr 2024

Yıldız Tech

Senior Backend Engineer

I worked on backend systems in the e-commerce/retail domain, focusing on real-time integrations and event-driven architectures. I developed a real-time stock control integration between CepteSok and Istegelsin, ensuring reliable propagation of stock updates and data consistency across systems. I also contributed to order, checkout, and payment-related backend flows, working with REST-based integrations and asynchronous communication patterns with a focus on reliability and correctness.

Node.jsMicroservicesREST APIsPayment integrationsMessaging systemsEvent-driven architecture
Nov 2022Mar 2023

Istegelsin (via Patika Global)

Senior Backend Engineer

I led development of a scalable serverless e-commerce backend built on AWS using Node.js and event-driven principles for reliability and growth. I worked on core services responsible for catalog, checkout, and order processing, focusing on low-latency responses and fault-tolerant backend design. I also integrated third-party payment providers (including Edenred and Sodexo) via payment gateways to expand checkout options while keeping flows consistent and maintainable.

Node.jsTypeScriptAWSServerlessLambdaDynamoDBPayment integrationsElasticsearchGraphQL
Nov 2021Nov 2022

Istegelsin (via Patika Global)

Backend Engineer

I worked as a backend engineer on a serverless e-commerce platform built on AWS. I developed backend services using AWS Lambda and API Gateway and contributed to DynamoDB data modeling based on access patterns and scalability requirements. I delivered core commerce features such as catalog, checkout, and order management, prioritizing maintainability, performance, and operational simplicity in production.

Node.jsAWSLambdaServerlessDynamoDBAPI GatewayNoSQL data modeling
Nov 2020Nov 2021

Faselis

Backend Developer

I independently developed and maintained a fully serverless internal backend system on AWS to support internal business workflows with minimal operational overhead. I owned the backend end-to-end, including architecture, implementation, deployment, and maintenance. The system prioritized simplicity, scalability, and long-term maintainability, and strengthened my experience in end-to-end backend ownership and cloud-native design.

Node.jsAWSREST APIsSwagger/OpenAPI MySQLDynamoDBLambdaServerless
Oct 2019Nov 2020

BiSU

Backend Developer

I developed backend APIs for a consumer-facing mobile application using Node.js and Express.js. I improved code quality by introducing unit tests for critical flows and iterating on existing API implementations to increase maintainability and reliability in production.

Node.jsExpress.jsRest APIsUnit testMongoDB
Sep 2017Oct 2019

HepsiEmlak (via Keytorc) & Vodafone (via Wipro)

QA Engineer

I worked as a QA Engineer across large-scale digital platforms, executing functional and performance testing for backend-driven systems. I wrote SQL queries for backend validation, collaborated with engineering teams on test planning and defect analysis, and supported test automation and reporting workflows in enterprise QA environments.

SQLFunctional testingTest automationPerformance testing