Burak A.

I help companies improve, modernize and extend existing .NET applications, including adding AI features that work reliably with their own data. 10+ years of C#/.NET across enterprise, payments, logistics and e-commerce systems. Based in GMT+3, with full overlap with European working hours. My strongest area is working inside existing systems: understanding the codebase, finding risks, improving performance, refactoring legacy code, and adding new features without breaking what already works. What I can help you with: → Maintaining and improving existing .NET applications → Modernizing legacy ASP.NET / ASP.NET Core systems and monoliths → Building and improving REST APIs with C# and .NET → SQL Server performance, query tuning and schema work → Integrating payments, RabbitMQ, Azure Service Bus, Redis, Elasticsearch and external APIs → Adding AI features to .NET apps: semantic search, RAG (answers grounded in your own data) and LLM integration with Microsoft.Extensions.AI → Improving reliability, security and maintainability AI integration, done like engineering: I build AI features the same way I build any other part of a system: measured and testable. In my public project SemanticSearchDemo, I built a retrieval pipeline in .NET with embeddings, pgvector on PostgreSQL, hybrid search and reranking, grounded answers with a chat model, and an evaluation suite that measures retrieval and answer quality instead of guessing. Examples of past work: - Building an enterprise customer portal in ASP.NET Core MVC (.NET 10, EF Core, SQL Server) for an international client: pages with reusable components and the Web APIs behind them. - Helped move a legacy monolithic parking management application to .NET 8 microservices with RabbitMQ, and set up GitHub Actions and Octopus Deploy pipelines. - Designed and built a SaaS product end to end with Python/FastAPI, PostgreSQL, React and AWS, including payment integration with hash verification and idempotent processing. - Integrated multiple carrier services into a unified package tracking system with C#, .NET, REST APIs, T-SQL and Blazor. - Developed Web API services for mobile and admin apps, with JWT authentication and payment integrations. - Built Web API services with Elasticsearch search and Azure Service Bus for a fashion e-commerce platform. Tech stack: C#, .NET 8, ASP.NET Core, ASP.NET MVC, Entity Framework Core, SQL Server, PostgreSQL, MySQL, REST APIs, Azure, Azure DevOps, Azure Service Bus, AWS, Docker, RabbitMQ, Redis, Elasticsearch, MongoDB, Blazor, React, TypeScript, Python/FastAPI AI: Microsoft.Extensions.AI, embeddings, vector search (pgvector), RAG, LLM evaluation How I work: - Clear communication and regular progress updates - Careful review before making changes - Clean, maintainable code - Practical solutions instead of unnecessary over-engineering - Comfortable with legacy systems, audits, maintenance and long-term improvements If you have an existing .NET application that needs maintenance, modernization, new features, or an AI feature built on your own data, send me a short description of the system and the problem, and I'll reply with how I'd approach it.