Mobile apps made with care.
Onyx29 designs and builds focused mobile apps for personal, everyday needs: private by design, simple to use, and built to last.
Small, careful, private.
Privacy first
We collect as little as possible. Where an app handles sensitive information, it is encrypted on your device before it is synced.
Clear by design
Complex rules and calculations, presented one simple step at a time, so that anyone can use them confidently.
No ads, no tracking
Our apps are paid for by the people who use them, not by advertisers. We never sell or share personal data.
Mayim
Taharas hamishpacha calendar · AndroidA private calendar for the laws of family purity. Mayim walks you through each count step by step on a Hebrew–Gregorian calendar, by your community's minhag, together with your spouse.
- Guided counting of vestos, the hefsek taharah, the seven clean days and mikvah
- Ashkenazi, Sephardi, Chassidish and Chabad starting settings, each explained with sources
- End-to-end encrypted sync between spouses' phones
Currently in private testing on Google Play.
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Questions about our apps, support requests, or privacy and data-deletion requests.