Your cycle is nobody’s business.
A period tracker that keeps everything on your phone. No account, no server, no subscription — one tool, bought once, yours forever.
On the App Store and Google Play soon.
Period apps grew subscriptions — then grew quizzes, articles, and streaks to pay for them.
All of it wrapped around what used to be a dot on a calendar — and all of it sitting on someone else’s server, holding the most sensitive health data a person has. The tool stopped working for the person using it.
Your cycle is nobody’s business.
Everything lives on the phone. No account, no email, nothing to breach, nothing to sell. There’s no server behind Peridot — so there’s nothing to hand over, because there was never anything to hand over. Your privacy is just that — yours.
Pay once. Own it forever.
One payment, then it’s yours. No recurring revenue means no reason to manufacture engagement — nothing to nag you back, nothing to upsell. Like the calendar on the wall: bought once, not rented.
A gem is something you own, not something you rent.
This is the whole app.
A calendar, a countdown, and a button to log. Logged days are solid; the days ahead are an estimate. No feed, no quizzes, no streaks to keep. You consult it for a few seconds, and then it leaves you alone.
Scroll the months — the dot is the whole idea.
A single most-likely day, and an honest window around it.
Peridot gives you one most-likely day plus a window that tightens as it learns you — never an oracle, never a fertility guarantee. The days it’s sure of are solid. The days it’s guessing are dashed, so the difference is never just a color.
Three flat steps of one green, deepest at the most-likely day. Predicted days are dashed; logged days are solid. No blend ever connects a fact to a guess.
The architecture is the argument.
Privacy here isn’t a promise we ask you to trust. It’s a consequence of how the app is built.