Loop Habit Tracker

Habit apps are among the most aggressively monetized categories: three habits on the free tier, statistics behind a purchase, ad removal behind another, data on someone else's servers, and frequently a stream of nagging notifications.

Loop is the clean exception. 10,129 stars, GPL-3.0, entirely free with no ads, no in-app purchases, no account, and no network permission requested — that last point being verifiable in Android's own permission settings, where you can confirm it is incapable of uploading anything.

It does not chase breadth, but the core is well built:

• Flexible habit types: yes/no completion (did I run today) or numerical targets (glasses of water, kilometres run), the latter with weekly goals.
• Flexible frequency: daily, three times a week, a few times a month. Not every habit should be daily, and this is handled better here than in many peers.
• A strength score. Rather than counting consecutive days, it computes habit strength with a time-decaying algorithm — missing one day does not reset anything, while sustained neglect gradually lowers it. This is psychologically healthier than a streak counter, since one missed day does not trigger abandonment.
• Detailed charts: calendar heatmaps, historical curves and day-of-week distribution, which reveals patterns like consistently breaking on weekends.
• Reminders at set times, without abusing notifications.
• Home screen widgets for logging without opening the app.

Data stays entirely on the device and exports to CSV or a database file for your own backups.

To be clear about:

• Android only. The author has not built for iOS, where open-source alternatives are scarce and the system Health app or the paid Streaks are the usual choices.
• Releases are infrequent. The current version, v2.3.1, is from August 2025 with continuing commits through 2026. This is a mature, stable application rather than a fast-moving project — arguably not a bad thing for a habit tracker.
• No cloud sync. Changing phones means exporting and importing manually, the inevitable cost of requesting no network access.
• It will not build the habit for you. The tool records and visualizes, and a reminder is only a reminder. True of every habit app, though some pretend otherwise.

Install from F-Droid or GitHub Releases; an official build is also on Google Play.