Hire the Best .NET Core Developers in Kyiv, UA

I develop AI agents, RAG systems, AI-powered document search, and workflow automation for business applications using Python, LangChain, OpenAI, Anthropic, Azure OpenAI, vector search, and modern LLM workflows. I also have 15+ years of production .NET experience with C#, ASP.NET Core, APIs, databases, cloud systems, integrations, logistics software, performance optimization, and legacy modernization. Numbers: - $80K+ earned on Upwork - 23 Upwork jobs - 1,100+ Upwork hours - 15+ years in software development - 50+ delivered software projects I can help with: - AI agents using Python, LangChain, OpenAI, Anthropic, and Azure OpenAI - RAG over documents, tickets, orders, products, reports, and knowledge bases - AI document search, semantic search, data extraction, and summarization - LLM workflows with validation, business rules, and human review - AI features inside existing .NET / ASP.NET Core applications - ASP.NET Core APIs, SaaS platforms, admin panels, and business systems - Legacy .NET Framework, ASP.NET MVC, WebForms, and VB.NET modernization - SQL performance optimization, background jobs, queues, caching, and integrations - Logistics software: TMS, WMS, order management, rate engines, shipment tracking, and carrier APIs For the AI/RAG part, I can use Python/LangChain. For production backend, APIs, admin panels, and enterprise integration, I can use .NET / ASP.NET Core. Tech stack: Python, LangChain, OpenAI, Anthropic, Azure OpenAI, RAG, embeddings, vector search, .NET, C#, ASP.NET Core, Blazor, SQL Server, PostgreSQL, MongoDB, Redis, EF Core, Dapper, Azure, AWS, RabbitMQ, Kafka.

I help SaaS and product companies modernize aging .NET applications — migrating legacy .NET Framework systems to .NET Core, rewriting outdated frontends with Angular, and fixing the bugs that have been piling up along the way — so your product stays secure, supported, and compliant instead of running on frameworks Microsoft no longer patches. I also build new features into existing .NET products and ship new web applications from scratch. If your app was built on .NET Framework 4.x or WebForms, you already know the problem: every month it gets harder to hire for, harder to patch, and harder to pass a security review. Customers ask about compliance. Auditors flag unsupported dependencies. Meanwhile, the team is afraid to touch the codebase because nobody's sure what will break. That's the work I do. A top-performing full-stack developer with 20+ years in Microsoft technologies, I own the full project lifecycle — analysis, design, development, deployment, maintenance — whether that means modernizing a legacy system, extending one that's working, or building something new from a blank repo. Pragmatic programming principles throughout: fast, secure, scalable software shipped without freezing new features for months. Recent wins: - Replaced a legacy e-commerce platform (.NET Framework 4.x / WebForms with DevExpress controls) with a ground-up ASP.NET Core rebuild — roughly 90% new code on both backend and frontend. Built a fast, responsive Angular UI (desktop + mobile), integrated Google Sign-In, Google Shopping product export, and ERP integration (product catalog pulled from the ERP, new orders pushed back). Also built an AI-powered tool that helps salespeople process purchase orders received by email/IM by matching free-form product requests against the catalog. - Modernized a legacy SaaS product built on .NET Framework — migrated vanilla JS to TypeScript with Webpack bundling, rewrote major jQuery components as Angular Elements, and built a new data-calculation module from scratch in Angular, integrated cleanly into the existing legacy site. - Remediated dozens of security vulnerabilities in a .NET Framework 4.x / WebForms application flagged by an independent security audit — minimal, surgical changes only, with zero regressions introduced. What I typically deliver: - Migration of ASP.NET Framework 4.x WebForms apps to ASP.NET Core - New features and modules built into existing .NET applications - New web applications and SaaS products built from scratch (ASP.NET Core + Angular) - Frontend rewrites from legacy JS / AngularJS / jQuery to modern Angular + TypeScript - Upgrades of outdated Angular apps (Angular 2–20) to the current Angular version - Bug fixes and stabilization of inherited .NET codebases - Integrations with HubSpot, Salesforce, Dynamics CRM, Microsoft Graph, Google Shopping / Merchant Center, AWS / Azure Core stack: C#, .NET Core, .NET Framework, Entity Framework, ADO.NET, ASP.NET MVC / Web API / WebForms, MS SQL, MySQL, Angular, TypeScript, HTML/CSS, Azure, AWS, Xamarin. If you're working on a .NET product — legacy or greenfield — send me the details. I'll tell you honestly what the work is and what it would take.

I am an AI developer and senior .NET engineer. I help companies build practical AI-powered products, RAG systems, chatbots, AI assistants, document search, and AI workflows that work with real business data. A strong background in .NET, backend systems, SaaS platforms, Blazor, Azure, databases, and production-ready architecture helps me build AI features as stable parts of real software products. My focus is on making the solution useful, reliable, and easy to maintain. I have worked with systems in finance, grocery, and other business domains, with attention to clean architecture, good performance, stable backend, and code that other developers can support and extend later. 🤖 AI Engineering - AI-powered applications and business automation - RAG systems / Retrieval-Augmented Generation - AI assistants and knowledge-base chatbots - AI agents and multi-step AI workflows - LLM integration and orchestration - OpenAI API, Semantic Kernel - Vector databases, including Qdrant - Document processing and semantic search - Prompt engineering and context management - Integration of AI features into existing .NET applications 🌐 Backend & Architecture - .NET Core / .NET Framework - High-load systems and distributed architecture - Microsoft Orleans - REST APIs and scalable SaaS platforms - Event-driven and service-oriented architecture - Performance optimization - Legacy system modernization 🎨 Frontend - Blazor - Angular - SPA development - HTML, CSS, TypeScript 🚀 Cloud & Data - Azure Cloud - Azure App Services - Azure Storage - SQL Server, PostgreSQL, Cosmos DB - Entity Framework, Dapper - Database design for business and AI-powered applications 📱 Mobile - .NET MAUI - Mobile application development - Contribution-level experience with the .NET MAUI ecosystem 🗄️ DevOps - Azure DevOps - CI/CD pipelines - Git - Deployment automation 📈 Experience & Results - Built AI-powered features, RAG systems, and assistants connected to real business data - Integrated LLMs with databases, APIs, documents, and internal knowledge bases - Built and scaled systems in finance and grocery domains used by thousands of users - Delivered full-stack solutions including backend, web, mobile, and AI features - Designed systems capable of handling real production traffic - Led development teams and mentored other engineers - Contributed to the .NET MAUI ecosystem - Migrated legacy systems from .NET Framework to modern .NET architecture - Improved performance, stability, and maintainability of existing applications 🤝 Let's connect! If you need an AI developer who can also build reliable .NET software behind the AI features, feel free to reach out and let’s discuss your project.

15+ years in .NET and C# area successfully covering Web | Mobile | Backend # From modern .NET / ASP.NET Core MVC and Blazor apps development to legacy WebForms support. # Data Storage in clouds or SQL/NoSQL databases accessed with Entity Framework. # From front-end side based on Angular / Vue / React to low-level support with pure JavaScript/jQuery/Ajax. # From MAUI and Flutter iOS/Android/Windows MvvM modern apps to old-fashioned WinForms. - Computer Science University Degree. - Analytics, legacy code migration, testing, support, documentation. - Long- and mid-term collaboration preferred. - Flexible working hours; ET/EDT time zone communication-friendly. - Ukrainian Development Culture (located in safe place now).