EAU is the first iOS app I've ever created. It started when a daily habit of LIDL donuts and croissants, Chinatown dumplings and cakes wrecked my skin — turns out water helps! NYC-only for now, it reminds you to drink enough to keep your skin glowing, plus there's a leaderboard to find out which NYC neighbourhood hydrates the most. Completely free, no ads, and zero data collection or tracking.
Disclaimer: EAU is for personal motivation only and is not a medical device or health product. It is not a substitute for professional medical advice.