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Justin O'Halloran

Work / Wealthee (co-founder)

Wealthee: a portfolio platform, built end to end

Co-founded with a financial advisor; as the only engineer I built the web dashboard, the React Native app, the Firebase backend and a shared TypeScript package.

Role
Co-founder and sole engineer
When
2020 – 2025
Stack
ReactReact NativeFirebaseTypeScriptSnapTradeBig.jsJestTurborepoGitHub Actions
Data cost change that forced a re-architecture
$500 → $5,000 / yr
Measured
Users
Never reached market
Measured

What it was

A portfolio-management platform for independent financial advisors and their clients. I co-founded it with a Toronto-based advisor and was the only engineer from 2020 until the partnership ended in April 2025.

The original build

  • A React web dashboard for advisors and a React Native app for clients, with push notifications and real-time asset updates.
  • A Firebase backend: Auth, Realtime Database, and Cloud Functions, including scheduled portfolio snapshots.
  • A shared TypeScript API package published to NPM in both ESM and CommonJS, so web, mobile and functions used one set of types and calls.
  • Money arithmetic in Big.js rather than floating point, and extensive Jest coverage on the financial-transaction logic.

Re-architecting around a price change

The market-data provider raised its price from $500 to $5,000 a year. Rather than pay it, I replaced the custom trading backend with SnapTrade, which turned the product into broker-connected execution through Wealthsimple, Questrade and others.

The 2025 rebuild

During a sabbatical I rebuilt the web dashboard and backend as a Turborepo monorepo with GitHub Actions CI/CD in about six weeks, working with an AI coding agent. That rebuild is public. It has no tests: I chose speed over coverage for it, and the test suite lives in the original repo.