Spendio

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In a nutshell

Spendio is an app for managing personal finances. I can add bank accounts, e-wallets, and cash; record income and expenses; move money between accounts; set budgets; schedule repeating bills; and save toward a goal. The dashboard shows my balance, my income and expenses, and where my money went this month.

Why I built this

I wanted one place to see where my money went without updating a spreadsheet. It also gave me a reason to build a real backend: an API, a database schema, and auth that I control from end to end.

What it solves

Spreadsheets get messy when money moves between accounts and bills repeat. Spendio keeps everything connected, so a transaction updates the right balance and the monthly summary at the same time.

How it's built

The app

Next.js 16 with the App Router, React 19, and Tailwind CSS 4. The dashboard, transactions, accounts, categories, budgets, recurring, and savings pages are all built.

Backend

An Express 5 API with PostgreSQL 17 and Drizzle ORM. Types and Zod schemas live in a shared workspace package, so the web app and the API validate requests against the same contract.

Balances

Money is stored as numeric(16,2) and handled as strings in TypeScript, and balance updates run in SQL inside one database transaction. A transfer or expense cannot leave an account balance drifting or add floating-point rounding.

Login

Better Auth handles email/password with verification and password reset, plus optional Google sign-in. Every /api/v1 route requires an authenticated session.

Testing & deploy

Vitest covers money handling, date helpers, email rendering, and API responses. In production the API runs as a systemd service behind nginx on AWS EC2, with PostgreSQL in Docker.

Result

Spendio is live here. The whole stack is mine: the Next.js app, the Express API, the Postgres schema, and the deployment. Building it taught me a lot about auth, database transactions, and keeping money numbers correct.