Exxpense
A personal finance platform for tracking spending, understanding cash flow, and making better day-to-day financial decisions.
Expense is a full-stack personal finance application built and deployed end to end, covering everything from data modeling and authentication to subscriptions and billing.
Personal finance data is sensitive, so the application needed real security, not just a login form. It also needed to support the workflows people actually use to track spending: importing data, visualizing it, and managing the subscription behind the product.
Secure authentication with field-level AES-256-GCM encryption, subscription billing via Razorpay, and responsive data workflows built on Zustand and TanStack React Query, including Excel import/export and data visualization. Deployed on Vercel with Neon PostgreSQL.
Sole developer — built and deployed the full stack, from schema and auth through billing integration.
Expense started as a personal tool to understand and reduce my own spending. Rather than reading transaction notifications from SMS or email, I designed it around explicit user-entered data, so the application only knows what the user chooses to record.
Privacy became a core technical requirement from the beginning. Financial data is encrypted before it is stored, which means the database does not contain readable transaction information.
From there, the application grew into a complete product around that model: authentication, encrypted storage, transaction management, data import and export, spending visualizations, and subscription billing. Each part was built around keeping the user's financial information useful to them without requiring access to their messages or email.
What started as a personal spending tracker became a complete privacy-focused finance application. It allows users to record and understand their spending without granting the application access to their SMS messages or email, while keeping stored financial data encrypted.
The final product covers the full journey from authentication and secure storage to transaction management, data import/export, spending visualization, and subscription billing.