A Flo alternative with no server to subpoena.
Flo settled with the FTC in 2021 over sharing users' health data with Facebook and Google, and now sells an "Anonymous Mode" as a feature. The Cycle Tracker has no mode. It has no network.
Cycle data is the most legally exposed category of personal record in several countries right now. Promises about handling it are only as good as the company, its next owner, and the jurisdiction it sits in. A file removes all three variables.
Why "anonymous mode" isn't the answer
A mode is a setting inside a product owned by a company that can be sold, breached, or ordered to comply. The only architecture that can't disclose your cycle is one that never received it.
What it records
Start and end dates, flow, symptoms and notes — and from those it predicts the next cycle and the fertile window with visible arithmetic you can check yourself, rather than a model you can't.
Keeping it private on a shared device
It's a file: name it whatever you like, keep it in an encrypted folder, or on a USB stick. There is no app icon announcing itself on a home screen.
The refund
Thirty days, one e-mail, money back. And the file stays yours either way.
Common questions
Does anything leave my device?
No. The file contains no network code — you can read it in a text editor and confirm that yourself.
Are the predictions as good?
They're based on your own history with the arithmetic shown. For most people that's as accurate as the model, and it's checkable.
Can I export the data for a doctor?
Yes — CSV out, or print the summary and take the paper.
What if I lose the file?
Back it up like any document. Nobody can restore it for you, which is the same reason nobody can hand it to anyone else.