Joel Steven S.

Full-Stack Engineer | Node.js, Go, React | Agentic AI & LLM Apps

Full-Stack Software Engineer | 5+ years shipping production systems I'm a full-stack software engineer with 5+ years building impactful, user-focused products across Fintech, Education, IoT, Web3, Sports, Dev Tools, and Health. I pair strong backend engineering with solid frontend craft to ship systems that are scalable, observable, and reliable in the hands of real users, not just demos. I'm now extending that foundation into Agentic AI engineering: building LLM-powered agents and RAG systems on top of the same production discipline (clean data flow, testing, and debugging) that my backend work is built on. Backend & Infrastructure - Languages: Node.js, Go (Golang), Python, TypeScript - Databases: PostgreSQL, MongoDB, Redis (SQL/NoSQL hybrid); pgvector for embeddings - Cloud & DevOps: AWS, Azure, GCP; Docker, CI/CD pipelines, Linux/VPS deployment - BaaS: Supabase, Firebase, Appwrite, AWS Amplify, PocketBase Frontend - Frameworks: React.js, Next.js, Vue.js, React Native, Capacitor, Flutter - Language & Styling: TypeScript, Tailwind CSS, Ant Design, Material-UI, Tailwind CSS, ShadCN Agentic AI Engineering - Frameworks: LangChain, LangGraph (stateful/multi-agent orchestration) - Patterns: RAG & agentic RAG, ReAct, tool/function calling, structured outputs, multi-agent workflows, MCP (Model Context Protocol) - LLMs: OpenAI, Anthropic Claude, open models via Ollama - Retrieval & data: vector databases (pgvector, Pinecone, Qdrant, Chroma), embeddings, semantic search - Observability & eval: LangSmith, Langfuse Testing & Quality - Test-Driven Development with Jest, Playwright, Cypress, Storybook, React Testing Library - End-to-end test pipelines and QA integrated across the development lifecycle Notable Projects - Serene Mind — a telehealth SaaS connecting therapists and patients with paid online sessions, built-in video/audio, and Stripe-style session payments. Next.js, React, TypeScript, Supabase, with custom CI/CD. (Core dev & tech lead) - SchoolBook — a finance, academics, and administration platform managing records for 1,000+ students across 20+ schools. React, Vite, TypeScript, Node.js, PostgreSQL. - GigGap — a skilled-labour marketplace for West Africa (electricians, plumbers, and other pros ↔ clients), live on both the App Store and Google Play. - Waziup IoT Lab — a learning platform for IoT serving 2,000+ daily active users. Go, React, Vite, TypeScript, PostgreSQL. (Lead developer) - Porai AI — an AI-powered math-solver app (in development). What Drives Me I build software that works and lasts. My approach centers on scalability, clean data flow, and user-centric design, and I like environments where I can investigate deeply, communicate findings clearly, and keep learning, most recently by moving into agentic AI. If you need someone who can own a problem end to end, let's talk.