Investigations

Todo App

TypeScript October 2025

A production-grade todo app with GitHub OAuth, Neon PostgreSQL, drag-and-drop ordering, and 90%+ test coverage.

Yes, it's a todo app — but it's the todo app I'd actually deploy to production. GitHub OAuth via Auth.js v5, Neon.tech serverless PostgreSQL via Drizzle ORM, drag-and-drop reordering with @dnd-kit, and a batch reorder API endpoint.

Testing is at 90%+ coverage (statements, functions, lines) with Vitest and React Testing Library. Playwright handles E2E. CI runs through GitHub Actions with a badge in the README.

The deployment target is Vercel with full configuration. There are 9 markdown docs covering everything from architecture to deployment. The middleware handles authentication checks.

Is a todo app exciting? No. But it demonstrates that I can take the simplest concept and build it with proper engineering: OAuth, serverless database, ORMs, drag-and-drop, CI/CD, high test coverage, and production deployment.

What this project demonstrates

GitHub OAuth via Auth.js v5
Neon.tech serverless PostgreSQL with Drizzle ORM
Drag-and-drop reordering with @dnd-kit
90%+ test coverage with Vitest + Playwright E2E
Deployed on Vercel with CI/CD
Batch reorder API endpoint

Technologies

Next.jsAuth.jsDrizzleNeonVercel

© 2026 Jonathan Leahy · v1.0.9