AI expense tracker2026
FinSight
FinSight is a full-stack personal-finance app that takes the manual work out of expense tracking. Transactions are categorized automatically by a large language model, and the whole experience is built on a secure, production-grade authentication and form architecture.
What I built
- Built the frontend in React 18 with Vite and TypeScript, and the backend as a NestJS + PostgreSQL service.
- Integrated LLM-based transaction categorization through the Gemini API for intelligent, automated expense classification.
- Implemented JWT authentication with a refresh-token rotation pattern — access token in memory, refresh token in an httpOnly cookie — with Axios interceptors for seamless token handling.
- Developed a configurable, schema-driven dynamic form builder using Zod / Yup validation and react-hook-form.
Tech stack
React 18TypeScriptViteNestJSPostgreSQLGemini API