Nept Track

OVERVIEW Nept Track is a private, offline-first daily planner for Android that combines a habit tracker, an expense and budget tracker, notes, a sketch whiteboard and a quick-capture inbox in one app. It needs no account and keeps every record on the phone. It is my own product, designed, built and published on Google Play.

THE CHALLENGE Most people manage their day with four or five separate apps: one for habits, one for money, one for notes and another for to-dos. Each asks for a sign-up, each stores data in someone else's cloud, and none of them see the full picture of the day. The goal was one calm app where capturing a thought, logging an expense or ticking off a habit takes only a few seconds, works without internet, and never forces a login.

THE SOLUTION I built Nept Track around a simple loop: capture first, sort later. Anything can be written into the inbox in one tap and turned into a task, an expense or a note afterwards. Typing "Spent 450 on transport" offers to log the expense directly. Habits, to-dos, money and notes share one design system and one local database, so the app can show a single honest view of the day and the week.

KEY FEATURES • Habit tracker with weekly schedules, goals, streaks and a 12-week heatmap • Fair streaks: rest days never break a streak • Exact-time reminders with a custom sound per habit, plus quiet hours • Focus time that turns on Do Not Disturb and restores sound afterwards • Expense tracker with category budgets, charts, projections and PDF/CSV reports • Notes with checklists, colours, pins, tags, photos and PDF attachments • Sketch whiteboard with an endless canvas and ready templates • Capture inbox with share-to-app from any other app • Optional Ask Nept AI assistant that only receives summaries, never note text • Fingerprint/face lock, backup export and restore • Light and dark themes in 16 languages, including Bangla, Hindi, Arabic and Urdu

TECHNICAL APPROACH The app is built with Expo, React Native and TypeScript. All records live in local SQLite through Drizzle ORM, with Zustand holding only UI and settings state, so the data layer stays type-safe and ready for optional sync later. Features the JavaScript layer cannot do reliably were written as custom Kotlin Expo modules: an exact alarm clock, Do Not Disturb focus mode, home-screen widgets, share intent, PDF rendering and direct saves to Downloads. Charts use react-native-gifted-charts, the whiteboard uses Skia, and animations run on Reanimated.

OUTCOME Nept Track is live on Google Play in 16 languages and is updated regularly, with version 2.3 adding the sketch whiteboard, templates and an assistant that can create habits, alarms and expenses. It shows end-to-end product ownership: product strategy, UX and visual design, offline data architecture, native Android modules, AI integration, store optimisation and release management.