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Just3 — Daily Big 3 Planner with Google Calendar Sync

·3 min read·#android#kotlin#compose#just3#calendar

Overview

Just3 is a daily productivity app built around one loop: Brain Dump → Big 3 → Time Box → Google Calendar → Review. Dump everything on your mind, pick the 3 that actually matter today, block time for them on your calendar, and review how it went.

  • Brain Dump — capture everything on your mind before committing to a plan for the day
  • Big 3 — narrow it down to the three tasks that actually matter today
  • Time Box — block calendar time for each of the Big 3, synced straight to the device calendar via CalendarContract — write once on save, update in place on edit, no manual import/export
  • Reminders — up to 3 reminders + 3 alarms per task, backed by CalendarContract.Reminders when a device calendar exists and AlarmManager as a fallback when it doesn't
  • Review — close the loop by reflecting on how the day actually went
  • Custom Material 3 theme — a fixed Deep Blue palette instead of dynamic wallpaper color, so the app keeps a consistent identity across devices

Tech Stack

  • Kotlin, Jetpack Compose
  • Room for local persistence
  • AlarmManager + CalendarContract.Reminders for the multi-alert reminder system
  • CalendarContract for direct read/write to the device calendar — no custom OAuth flow, no backend
  • Google's standard permission flow (first request → rationale → settings)
  • Pretendard Variable font, bundled for instant loading

How to Download and Test

Just3 is currently in closed testing on Google Play. Testing requires three steps, done in this order:

  1. Join the Google Group — Play Console checks group membership before it lets you opt in, so this comes first. → https://groups.google.com/u/1/g/just3-beta-testers
  2. Opt in to the closed test — once you're in the group, open this link and accept becoming a tester; it whitelists your Google account for the Play Store listing. → https://play.google.com/apps/testing/com.youngdevsbin.just3
  3. Install from the Play Store — after opting in, the app becomes installable from its normal Play Store page. → https://play.google.com/store/apps/details?id=com.youngdevsbin.just3

Note: if you install before completing step 2, the Play Store page will show the app as unavailable. It can take a few minutes for the opt-in to propagate after step 2.

Google also requires a closed test to hold a minimum number of active testers for a set period before it's eligible to move toward production — installing and immediately uninstalling doesn't count. So the actual ask is to keep the app installed for about two weeks and open it now and then. Thanks for helping test it out 🙏