Ethos Finance

Project Overview

Personal finance platform that tracks banking, credit cards, loans, and investments on a strict ledger so net worth is not inflated by double-counted repayments. Balances are encrypted before they reach PostgreSQL, market prices sync from Yahoo Finance and AMFI, and a Gemini copilot can query the books only after the user confirms any write.

Backend & Engineering Highlights

• —Built the full stack with NestJS, React 19, TypeScript, Prisma, and PostgreSQL, covering accounts, transactions, holdings, goals, and SIP schedules.
• —Modeled six transaction types — expense, income, transfer, investment, redemption, and adjustment — so a credit-card payment is a transfer between accounts, not a second expense.
• —Encrypted balances, amounts, credit limits, loan principals, and holding quantities with AES-256-GCM before storage, and hashed passwords with bcrypt.
• —Wrapped balance updates in interactive Prisma transactions with row-level locks so concurrent writes cannot desynchronize account totals.
• —Synced Indian and global equity quotes from Yahoo Finance and mutual fund NAVs from AMFI, then computed invested capital, market value, and unrealized P&L.
• —Split loan EMIs into interest (expense) and principal (transfer against the loan), and tracked credit-card billing cycles, due dates, and utilization.
• —Shipped a SIP scheduler for weekly and monthly installments, with a pending-installment banner that posts the ledger entry in one action.
• —Added a streaming Gemini copilot and an MCP server so in-app and external agents can read accounts and propose transactions that stay pending until the user confirms them.