Eylem Seyhan
Computer Engineer focused on backend development with experience in modern .NET architectures, microservices, distributed systems and scalable web applications. I enjoy building performant software while creating clean and engaging user experiences.
About Me
I build the parts of a product people never see, and care a lot about the parts they do.
Computer Engineering graduate from Trakya University, currently a Full Stack Engineer at PND Core, working across .NET and React — CQRS to keep read and write paths independent, and MagicOnion over gRPC for strongly-typed real-time communication between services and clients.
Before that, nine months at Senswise on a multi-tenant .NET architecture: CQRS and event-driven workflows, background jobs for scheduled tasks, RabbitMQ queues watched for stuck and failed messages, Elasticsearch for log tracking, and a steady diet of LINQ tuning and legacy refactoring. Two of the projects below started as internships — PowerPlantApp at Enerjisa Üretim, the sports club system at DSİ — which is where I learned that shipping something real beats reading about it.
I move to the frontend when a project deserves one: React, Next.js, Vue 3 and Tailwind CSS. I take freelance work too — Orliva Medikal's corporate site is a recent one, built end to end from catalogue structure to launch. Outside of shipping code I write technical articles on Medium — on CQRS, Keycloak identity migration, connection pooling and data structures — and for a couple of years I recorded test books aloud for visually impaired students.
- Full Stack Engineer at PND Core — .NET and React, CQRS on the backend, MagicOnion over gRPC between services and clients.
- Getting Blossom onto iOS: landscape touch controls, and holding frame time on the mobile renderer without giving up the shaders.
- Working through a data structures series on Medium — Big-O and array vs. linked list went up this month.
Public repositories
Technical articles
Years building .NET
Skills & Tooling
The stack I reach for, ordered by how often it shows up in my work.
Backend
01- C#
- .NET
- ASP.NET Core
- Entity Framework Core
- CQRS
- MediatR
- REST API
- Microservices
- RabbitMQ
- Redis
- Elasticsearch
- Keycloak
- gRPC
- MagicOnion
- Onion Architecture
Frontend
02- React
- Next.js
- TypeScript
- JavaScript
- Vue 3
- Angular
- Tailwind CSS
- Framer Motion
- Ant Design
- Bootstrap
- HTML
- CSS
Database
03- PostgreSQL
- SQL Server
- Firebase Firestore
- Redis Cache
Tools & DevOps
04- Docker
- Git
- GitHub Actions
- Rider
- Visual Studio
- VS Code
- Postman
- DBeaver
- Swagger
- Figma
- Vercel
Selected Projects
Production work and personal builds, most recent first.
Project 1 of 7
I believe good software is both art and engineering.
Experience & Education
Where I have been building, and what I was building with.
- Jul 2026 — PresentPart-time
Full Stack Engineer · PND Core
Working across the stack on .NET and React applications. Backend features are structured around CQRS so read and write paths stay independent, and MagicOnion over gRPC gives strongly-typed real-time RPC between services and clients.
- .NET
- React
- CQRS
- MagicOnion
- gRPC
- Sept 2025 — May 2026Full-time · İstanbul, Türkiye
Backend Developer · Senswise
Worked on a multi-tenant architecture, applying CQRS and event-driven principles to manage asynchronous workflows, and built and maintained background jobs for scheduled tasks. Monitored RabbitMQ queues to identify message processing issues, analysed stuck and failed messages, and supported system stability through log tracking in Elasticsearch. Wrote LINQ queries, optimised data access performance and refactored legacy code.
- .NET
- CQRS
- Event-Driven
- Multi-tenant
- RabbitMQ
- Elasticsearch
- PostgreSQL
- LINQ
- Background Jobs
- Apr 2025 — Jun 2025Full-time
Software Developer · DDI Technology
Developed unit and integration tests for NLua-integrated .NET modules, and wrote the internal documentation covering onboarding and day-to-day use.
- Aug 2024 — Sept 2024Internship · Ataşehir, İstanbul, Türkiye
Intern · Enerjisa Üretim
Where PowerPlantApp came from: an internship on energy production systems that turned into a full ASP.NET Core MVC monitoring application for tracking plants, efficiency ratios and generation capacity.
- ASP.NET Core MVC
- EF Core
- SQL Server
- Jul 2024 — Aug 2024Internship
Intern · DSİ — State Hydraulic Works
Built the sports club management system for DSİ's athletic programmes — student and branch records, course registration and a participation dashboard.
- ASP.NET MVC
- SQL Server
- Mar 2024 — Jun 2024Internship
Artificial Intelligence Intern · Abdi Business Technologies
Built an AI-powered question-answering system with LangChain and OpenAI that pulls answers out of PDF documents, using vector indexing and prompt engineering.
- Python
- LangChain
- OpenAI
- RAG
- Vector Indexing
Earlier roles
- Student Affairs AssistantTrakya UniversityMar 2025 — Apr 2025
- Sales ConsultantDAGİJun 2022 — Sept 2022
- Denizaşırı Online InternDenizBankDec 2021 — Jan 2022
Education
B.Sc. Computer Engineering · Trakya University
Coursework across data structures, algorithms, databases and software architecture — the same ground I now write about on Medium.
Volunteering & Certifications
Work that isn't measured in commits.
Volunteering
Mühendislik & Proje Community
Sat on the community's board as a member of its Research and Development committee, across two and a half years of student engineering projects.
Ders Ortağım
I recorded test books aloud for visually impaired students, turning printed practice material into audio they could actually study from. Accessibility stops being an abstraction once you have read a full exam paper into a microphone.
Yetkin Gençler (YetGen)
Took part in the Yetkin Gençler development programme as a trainee.
Certifications
- Yarınlar Seninle Mümkün ProgrammeSabancı HoldingNov 2023 — Mar 2024
A selective development programme run by Sabancı Holding with Çimsa, Enerjisa, SabancıDx and Sabancı University: five trainings across five areas plus 22 workshops on digital competencies and technology.
Latest Articles
I write about backend architecture, .NET and the fundamentals worth revisiting.
Let's build something
I am in a part-time role and not looking to move, but I take on freelance projects and I am always up for an interesting problem. The fastest way to reach me is email.
Or email directly
eylemseyhaann@gmail.com