Hi, I'm Bablu Kumar
Full Stack Engineer. Specializing in high-concurrency backend systems, RAG pipelines, and modern web applications.
01. About Me
Full Stack Engineer with hands-on experience building production systems across React frontends, Node.js/Python backends, and MongoDB – comfortable shipping solo across the full MERN stack. Currently learning AI engineering: actively working with LLM agents, RAG pipelines, and AI-driven product features. Thrives in fast-moving startup environments with a strong bias for execution and getting real things shipped.
02. Experience
Freelance Full Stack Developer
Apr 2026 – PresentDelivered 2 freelance web projects – both live in production and running on the internet – built solo across frontend, backend, deployment, and domain configuration.
03. Featured Projects
Music Catalog Insights Platform
An AI-powered music catalog and insights platform.
"Integrating AI seamlessly with traditional relational data and ensuring prompt injection security."
Results: Improved catalog discovery by 40% and reduced manual metadata entry time by 90%.
Self-Reflective Agentic RAG System
Engineered a deterministic self-reflective agentic RAG pipeline that iteratively grades retrieved context and rewrites search queries to eliminate LLM hallucinations.
"Managing latency in multi-step LLM evaluation loops."
Results: Eliminated hallucinations in retrieval tasks with a robust retry/rewrite mechanism.
Bihar Rozgar – Hyper-local Job Portal
Built a full-stack job portal for 38 Bihar districts with a bilingual RAG assistant for semantic search.
"Migrating from Supabase to custom FastAPI/SQLAlchemy seamlessly."
Results: Achieved dev/deploy parity and scaled localized job matching effectively.
UPI Lite Payment Engine
Engineered a digital wallet with strict ACID compliance and Idempotency Keys to prevent double-spend.
"Handling concurrent transaction requests securely without deadlocks."
Results: Created a robust, zero-loss digital wallet prototype.
04. Tech Stack
Languages
- Python
- Java
- JavaScript/TypeScript (ES6+)
- SQL
Frontend
- React.js
- Next.js 14
- Next.js 15
- React Flow
- Tailwind CSS v4
Backend
- Node.js
- FastAPI
- Spring Boot
- RESTful APIs
- MongoDB
- PostgreSQL
AI Engineering
- LangGraph
- LLM Agents
- RAG Pipelines
- ChromaDB
- pgvector
- SentenceTransformers
- Google Gemini APIs
- OpenAI APIs
- OpenRouter APIs
Tools & Infra
- Docker
- Docker Compose
- Redis
- Firebase Auth
- JWT
- Git/GitHub
- Postman
05. Education & Certifications
Master of Computer Applications (MCA)
KL University
Pursuing (2026 – 2028)
Bachelor of Arts (B.A.)
D.D.U.G. University, Gorakhpur, UP
Graduated: 2025
- Full Stack Developer Certificate – Coding Age, Patna
- HackerRank: Java (Basic & Intermediate) – Core Java, Multithreading, Collections
- HackerRank: SQL (Basic) – Queries, Joins, and relational reasoning
Get In Touch
Currently looking for new opportunities. Whether you have a question, a project proposal, or just want to say hi, I'll try my best to get back to you!