Streakly is a free Android habit tracker with no INTERNET permission — it physically can't send your data anywhere. No account, no ads, no trackers, no paywall.
Weekly goals count weeks, not days, so a rest day never breaks your streak. Freeze days for illness or travel. Counted habits (8 glasses, 30 min), heatmaps, a home-screen widget, smart reminders, and Health Connect habits driven by your watch — all on-device. JSON backup when you want it.