About this app
Transform your life one habit at a time with 66 Challenge - the science-backed app that helps you build lasting habits in just 66 days. WHY 66 DAYS? Research shows it takes an average of 66 days to form a new habit. We've built the perfect system to guide you through every single day. KEY FEATURES: - Daily Habit Tracking - Mark your habits complete each day and watch your streak grow - Progress Visualization - See your 66-day journey unfold with beautiful progress tracking - Streak Protection - Stay motivated with streak counts and milestone celebrations - Progress Photos - Capture your transformation with optional daily photos - Friends & Social Feed - Follow friends, celebrate their wins, and stay accountable together - Squads - Join or create groups to challenge habits together - Achievements - Unlock badges as you hit milestones on your journey - Reminders - Never miss a day with customizable notifications BECOME UNDENIABLE Whether you want to exercise daily, read more, meditate, or build any positive habit - 66 Challenge gives you the structure, motivation, and community to make it stick. Start your 66-day transformation today. --- Terms of Use: https://spiffy-muskmelon-f8f.notion.site/Terms-of-Service-66-Challenge-2f456f682ccc8026ac42f9567c526f57 Privacy Policy: https://spiffy-muskmelon-f8f.notion.site/Privacy-Policy-66-Challenge-1e956f682ccc80f18d6ad0a347d8707f
Latest release
What’s New
Fixed a bug where the day could advance twice in one evening. Reminders now stay on after reinstalling. New share card. Badges now reward your longest streak.
Audience growth
Ratings growth
Baseline captured. Growth appears after the crawler observes a changed rating count.
Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.
Price tracking
Price intelligence
First snapshot captured. The trend line starts after the next crawler price observation.
- First observed Sep 4, 2026 · 7:44 AM Free