Rythena starts with a practical question: what would make today easier to understand? The app combines clear dates, a current period-day counter and optional observations, without requiring every category to be filled.
Built around your choices
Core tracking works without an online account. You choose whether to use fertility estimates, cloud services, Apple Health permissions or private partner sharing. Free tracking and full history remain useful without Plus.
Clear about limits
Period and fertility predictions are calendar estimates. They do not confirm ovulation, diagnose a condition or provide contraception. A report describes saved records; it does not establish their cause.
About this website
The labelled screenshots show the upcoming iOS and Android apps using synthetic examples. Public release is pending. Guides explain actual product behavior and articles explore practical tracking questions. Our editorial page explains AI assistance, sourcing and corrections.
Talk to us
Use Rythena support for product questions or corrections. Please do not send journal recovery keys or private pairing secrets.