Vitalii A.

Senior Full-Stack & Cross-Platform Engineer | AI/LLM, Web, Mobile, Desktop Looking for an all-around Senior Software Engineer who can tackle any technical challenge - from high-level AI agents to low-level reverse engineering and cross-platform apps? With 15+ years of software development experience, I help businesses design, build, and scale complex applications across all major platforms and stacks. Whether you need a full-stack web application, an autonomous AI-driven workflow, or a high-performance cross-platform system, I deliver clean, maintainable, and scalable code. TECHNICAL CAPABILITIES AI & LLM Integration (Agentic Systems) 1.1. Building custom AI agents, fact-checking systems, and intelligent ad-selection engines. 1.2. Frameworks & Tools: LangChain, LangGraph, Semantic Kernel, n8n (no-code/low-code). 1.3. Providers & Models: OpenAI API, Anthropic, DeepSeek, Ollama (local LLMs), Hugging Face, OpenCV. Full-Stack Web Development 2.1. Backend: Python (FastAPI, Flask, Django), C# (ASP.NET Core, CoreAPI, Razor), PHP (Laravel, Drupal, WordPress), Node.js. 2.2. Frontend: React, Next.js, TypeScript/JavaScript, HTML5/CSS3. 2.3. Databases & ORMs: PostgreSQL, MySQL, MSSQL, MongoDB, CosmosDB, Neo4j, pgvector. Entity Framework, SQLAlchemy, Prisma/Next ORM, Django ORM. Desktop Application Development (Windows, macOS, Linux) 3.1. Cross-platform and native GUI apps: Qt (C++), WPF, Avalonia UI, Windows Forms, MFC. 3.2. Low-level system programming, socket communication, automation tools, and local encryption. Mobile Development 4.1. Cross-platform apps with React Native. 4.2. Native Android development (Java, C++ / NDK). 4.3. Networking utilities, proxy systems, and embedded WebViews. Cloud, DevOps & Automation 5.1. Cloud Platforms: AWS (Lambdas, Docker containers), Azure, GCP, Vercel. 5.2. Web Scraping & Automation: Human emulation algorithms, anti-bot bypass, automated checkouts, Selenium. 5.3. Reverse Engineering & Low-Level: .NET, Java bytecode, x86/x64/ARM Assembly. FEATURED PROJECTS & HIGHLIGHTS AI Fact-Checking Chat Engine: Engineered an embeddable LLM-powered fact-checking system using LangGraph + FastAPI, integrating custom web scrapers and computer vision (OpenCV). AI Ad Selection & Analytics: Built a real-time ad targeting system based on text/chat analysis using LangGraph, FastAPI, and cross-platform embedding SDKs. Enterprise Software Suites: Developed complex backend systems (C# CoreAPI, ASP.NET, Laravel, Node.js) managing real-time hardware & IoT control. Fintech & Microservices: Developed cloud-native financial services using C# and Python/Flask microservices deployed on AWS (Docker & Lambda). WHY WORK WITH ME? True Universal Mindset: I select the right tool, framework, and architecture for your specific goal rather than sticking to just one stack. End-to-End Ownership: From database design and cloud infrastructure to UI/UX implementation and deployment. Clean Code & Reliability: 20 years of writing maintainable, secure, and well-documented software. Got a complex project or technical challenge? Let's connect and discuss your requirements!