Doan T.

👋 Hi! I'm an AI & Full-Stack Engineer with 3+ years of experience building production-ready LLM applications, RAG systems, AI agents, automation workflows, and scalable web platforms using TypeScript, Node.js/NestJS, React/Next.js, PostgreSQL, Redis, and cloud infrastructure. 🤖 AI & LLM Engineering: I build AI-powered applications using OpenAI, Claude, Gemini, and other LLM APIs, including AI chatbots, intelligent assistants, AI agents, tool calling, automation workflows, and custom AI pipelines. I focus on building reliable AI features that integrate naturally into real-world products rather than simple LLM API integrations. 📚 RAG & Knowledge Systems: I develop RAG pipelines, semantic search, document processing, embeddings, vector search, and knowledge management systems using technologies such as PostgreSQL/pgvector and Redis. I focus on retrieval quality, context construction, source citation, and scalable document-processing workflows. I have worked on projects such as SmartRAG, a knowledge platform combining document processing, AI-generated knowledge, PostgreSQL/pgvector semantic search, background processing, AI answer generation, citations, and MCP integration. 🎥 AI Applications & Assistants: I have also built AI-powered applications involving interactive AI Avatars, conversational AI, information extraction, and intelligent travel planning, integrating AI capabilities into modern web applications and user workflows. 💻 Full-Stack Development: I build modern web applications using React, Next.js, Node.js, NestJS, TypeScript, and PostgreSQL, covering everything from responsive frontend interfaces to scalable backend APIs and business logic. ⚙️ Backend & Real-Time Systems: I design secure REST APIs, WebSocket-based real-time systems, authentication and authorization, database architectures, and background processing using Redis, BullMQ, Prisma, and PostgreSQL. I focus on clean architecture, reliability, and maintainability. ☁️ DevOps & Cloud: I deploy and maintain production applications using Docker, Nginx, Linux, CI/CD, Railway, Firebase, Cloudflare, and cloud infrastructure. I can handle the full lifecycle from development and deployment to monitoring, troubleshooting, and optimization. 🔒 Security-Focused Engineering: I build security into applications through proper authentication, authorization, API security, environment management, secure infrastructure configuration, and defensive coding practices. I also have experience in web application and API security testing. 🚀 Automation & Integrations: I develop automation solutions for business workflows, desktop applications, API integrations, bots, browser automation, and custom software. I can connect AI systems with external APIs, databases, webhooks, and existing business processes. 📈 Performance & Scalability: I optimize applications for latency, reliability, scalability, and cost using efficient database queries, caching, asynchronous processing, background workers, and appropriate system architecture. 🤝 How I Work: I focus on understanding the actual business problem before choosing the technology. I can work with an existing codebase, improve the current architecture, or build a new system when necessary. My goal is to deliver practical, maintainable, production-ready solutions rather than unnecessary complexity. 💼 What I Can Help With: AI / LLM Applications RAG & Vector Search AI Agents & Tool Calling AI Chatbots & Assistants AI Automation Smart Knowledge Systems React / Next.js Applications Node.js / NestJS Backend REST APIs & WebSockets PostgreSQL / pgvector / Redis Cloud & DevOps API & Web Security Custom Automation & Integrations If you have an AI product, SaaS platform, backend system, automation workflow, or existing application that needs AI capabilities, I can help design, build, integrate, and deploy it end-to-end.