Build idea · Beginner
A habit tracker
Check off a box, keep a streak alive — the CRUD app that quietly teaches you how to handle time.
A habit tracker lets you define daily or weekly habits, check them off each day, and watch a streak grow. The core feature is the streak engine — computing current and longest streaks from a raw log of completions while correctly handling timezones, missed days, and habits that aren't due every day. It's the friendliest possible intro to modeling time-based data, which is exactly where most "simple" apps quietly get hard.
What you'll learn
- →Modeling time-series data properly: habits and completions belong in two separate tables, not one row you keep overwriting
- →Writing streak logic — the deceptively hard part, where timezones and 'did I actually miss yesterday?' will bite you
- →Enforcing per-user data isolation with auth and row-level security so nobody sees anyone else's habits
- →Building an optimistic UI so ticking off a habit feels instant instead of waiting on a round-trip
Take it further
- +Add a GitHub-style contribution heatmap so you can see months of consistency at a glance
- +Send a daily nudge email with Resend, triggered by a Vercel Cron job that checks who hasn't logged today
- +Add 'streak freeze' or scheduled habits (e.g. Mon/Wed/Fri only) — a real test of whether your streak engine actually holds up