Raj Chhapariya

Python, OpenAI API, BM25, NumPy, Pydantic

• Built a retrieval-augmented generation pipeline that plans queries, retrieves information, checks evidence quality, and generates answers only when supported by evidence. Weak evidence triggers a retry or a refusal, and every answer includes source citations.
• Combined semantic search with BM25 keyword search using Reciprocal Rank Fusion to improve retrieval accuracy. Added handling for multi-part questions and contradiction detection.
• Built an evaluation framework measuring retrieval accuracy, citation quality, hallucination rate, and cost, to systematically assess output quality.
• Tested extensively with a mocked API and budget limits: 87 automated test cases pass without live API calls.

Python, LLMs, DuckDB, Streamlit

• Built an agent that answers plain-English questions about datasets using four fixed tools (SQL queries, charts, statistics, and clarification), avoiding open-ended code execution for safer, more predictable behavior.
• Restricted the system to read-only SQL and built a check that verifies the model's numerical claims against the underlying data, to catch unsupported or incorrect claims.
• Evaluated the system on 20 questions and edge cases; it selected and executed the correct tool in every case, with limitations documented.
• Built a Streamlit interface supporting CSV upload, automatic profiling, interactive charts, and report export.

trulyapp.online ·Instagram: @trulyapp.online

Architected and engineered an intentional social video platform for young urban Indians (ages 18–30) to meet through structured 60-minute video circles, featuring double-blind mutual matching with a 2-hour SLA, Panda CSS design system, and Neon serverless PostgreSQL with Drizzle ORM. Implemented pessimistic row-locking (SELECT ... FOR UPDATE) across 8-seat allocations to eliminate race-condition overbooking, UUIDv7 primary keys for index efficiency, and a Transactional Outbox pattern for asynchronous event processing.

atsroast.com ·Case Study

Built and launched an AI-powered resume tool, using Next.js, TypeScript, Supabase (PostgreSQL with Row Level Security), and the OpenAI API, including a spatial ATS parser, zero-duplicate action verb rewriter, and ATS-safe PDF export.

Varanasi, India

Owned and operated an independent restaurant for six months, managing staff, budgeting, pricing, and vendor relationships.