Todo App

A local-first task list that installs like an app and works fully offline, with optional Google sign-in that syncs tasks and labels across devices. New tasks land at the top, or switch to grouping by due date, with Vital tasks, labels, search, and delete with Undo.

What it does

• Works offline: tasks live in IndexedDB on the device, and edits made in two tabs at once don't silently replace each other
• Optional Google sign-in syncs tasks and labels across devices; without it, nothing leaves the device
• Installs like an app and opens offline: a service worker precaches the whole static export and never caches Supabase data
• Newest first, or grouped by when it's due: Overdue, Today, Tomorrow, Upcoming, No date and Done, re-grouped at midnight
• Vital tasks and colour labels, with search and filters that survive a reload
• Add, edit in place, complete, and delete with Undo; Ctrl+Z works too
• Keyboard and screen-reader friendly: n adds, / searches, a skip link, and no axe violations, contrast included

Architecture

Data model

Dexie over IndexedDB on the device is what the interface reads and writes. Signed in, tasks and labels mirror to two Supabase Postgres tables under row-level security, so each account only ever reads and writes its own rows.

API

No API routes. A client-side sync engine pushes and pulls in batches against Supabase. A database trigger settles conflicts: last write wins, a device clock running fast can win by at most five minutes, and a deletion is final.

Auth

Optional Google sign-in through Supabase Auth. Without an account the app works fully offline on one device.

Hosting

Vercel serves the static export as plain files, and a service worker precaches it so it installs and opens offline. Supabase for Postgres and sign-in.