Backend Developer | Analyst Programmer | AI Application Developer
I build backend systems, full-stack web applications, and AI-powered applications, with a focus on RESTful APIs, RAG systems, workflow automation, payment integration, and production-ready system design.
- Backend development with Java, Spring Boot, Node.js, NestJS, and FastAPI
- AI application development with RAG, embeddings, reranking, and LLM integration
- Full-stack development with TypeScript, React, and Next.js
- API gateway, payment workflow, queue system, and document processing
- local-rag — Local Retrieval-Augmented Generation experiment for private knowledge base workflows.
- raspberry-pi-5-local-rag — Local RAG system designed for Raspberry Pi 5 deployment.
- rag-news-summary — AI news summarization project using RAG-style retrieval and LLM generation.
- go-chatgpt-api — OpenAI-compatible API proxy for AI service integration.
- openai-privacy-filter — Privacy filtering layer for AI API requests.
- queue-room — Virtual waiting room system for traffic control and queue-based access.
- libreoffice-api — Document conversion API for office file processing and AI ingestion workflows.
- nest-pusher — Notification / push service backend.
Languages: TypeScript, Java, Python, Kotlin, Go
Backend: Spring Boot, Node.js, NestJS, FastAPI
Frontend: React, Next.js
AI: RAG, Embeddings, Reranking, LLM Applications, Sentence Transformers
Database / Search: MySQL, MongoDB, Elasticsearch, Weaviate, Redis
Cloud / DevOps: Docker, AWS EC2, S3, Google Cloud Run, Cloudflare Workers
- Email: leokwsw@gmail.com
- LinkedIn: linkedin.com/in/leokwsw