Şafak SönmezSenior Backend Engineer
Fintech · Real-Time Systems · Distributed Architecture
I design and build backend systems end-to-end — from architecture and implementation to deployment, reliability, and production operations. My focus is fintech, trading platforms, payment systems, and real-time distributed services.
Building systems that hold under pressure
My work is centered on backend systems that operate at scale — APIs handling high transaction volumes, distributed services processing real-time events, and fintech infrastructure where correctness is non-negotiable.
I own the full lifecycle: system design, implementation, infrastructure, observability, and production operations. I work in .NET, Node.js, and Go, and I understand the tradeoffs that matter when building distributed systems in regulated, latency-sensitive environments.
When the product demands it, I also deliver full-stack. But my strongest contribution is always at the system and backend layer — designing for reliability, scalability, and long-term maintainability.
Domain Focus
Case Studies
A selection of systems I've designed, built, and operated in production.
Technical Stack
Core capabilities, grouped by function.
Languages & Frameworks
Backend & Architecture
Messaging & Real-Time
Data
Infrastructure
Domain Expertise
Frontend
— supporting capabilityWork History
Backend Developer / Technical Lead
Incodi Software Development- Own backend architecture and technical direction for a self-service trading and operations platform
- Integrated MetaTrader 5, payment providers, and KYC flows with focus on reliability and maintainability
- Built real-time and transactional services with .NET, Redis, RabbitMQ, and Socket.IO
- Operated across backend, deployment, and infrastructure layers with Docker, Kubernetes, and CI/CD
Backend Developer / Technical Lead
Yukatech AS- Progressed to backend lead role driving delivery for RouteControl and YukaTrack products
- Designed telemetry ingestion pipeline with Teltonika binary parsing and real-time geolocation processing
- Implemented distributed backend components using Go, Node.js, MongoDB, Redis, RabbitMQ, and gRPC
- Supported production-focused backend work across service design, debugging, and deployment
Backend Developer (Part-Time)
GoAction- Contributed to a serverless product stack using AWS Lambda, API Gateway, DynamoDB, and Node.js
Freelance Full Stack Developer
Independent- Built commercial projects with .NET, Node.js, React, Python, and Laravel
- Delivered integration-heavy and real-time applications for various clients
Technical Notes
Engineering observations from building fintech, real-time, and distributed systems.
Designing Reliable WebSocket Infrastructure at Scale
Connection lifecycle management, fan-out patterns, and ensuring delivery guarantees in high-concurrency socket systems.
Payment Integration Architecture That Doesn't Break
Idempotency, provider abstraction, webhook reliability, and building payment flows that hold under network failures.
Distributed Systems Tradeoffs in Fintech Products
Consistency, availability, and partition tolerance decisions when the system handles money and compliance state.
Let's Talk
I'm open to senior backend, lead, and staff-level roles in fintech, real-time systems, and distributed architecture. If you're working on something technically interesting or operationally complex, I'd like to hear about it.