What is the best period tracker for privacy?

There is no single tracker that is the most private for every woman, but there is a short, checkable list of things that separate a tracker that actually protects your data from one that only says it does, and most mainstream period trackers fail at least one of them.

• Has it actually been caught sharing your data, not just promised not to? This has already happened, more than once, to trackers used by millions of women. In 2021 the U.S. Federal Trade Commission found that Flo Health, maker of one of the most downloaded fertility tracking apps, had shared users' health data with Facebook, Google and other companies for years while promising to keep it private, and ordered the company to get users' explicit consent before sharing it again. In 2023 the FTC took the same kind of action against the maker of the ovulation tracking app Premom, barring it from sharing health data for advertising after finding it had done so without consent. A privacy policy that says it values your privacy is a promise; a regulator's order against a specific company for a specific violation is a record.
• Has it been reviewed by someone with no reason to flatter it? A review by the Mozilla Foundation of popular period and ovulation trackers tested the apps directly rather than taking their marketing at face value, and found that most collected far more data than they needed and were unclear about who saw it afterward. An outside audit like that is worth more than a tracker's own description of itself.
• What does it say it will do if it receives a legal demand for your data? The Electronic Frontier Foundation notes that most period tracker privacy policies include a clause allowing the company to hand data over to comply with legal process, meaning a subpoena, not necessarily a warrant, can be enough. That clause is standard even in otherwise careful apps, so the real question is not whether it exists but how much the company actually holds to hand over in the first place: a tracker that stores less, and encrypts what it does keep, has less to give up regardless of what the policy says.
• Can you actually delete what you logged, and does the app say what deleting it does? A tracker that lets you export your data and permanently delete it on request is behaving differently from one that stays silent on the question, or that only closes your account while keeping the records behind it.

For a Muslim woman, this list carries more weight, not less. A tracker built to tell hayd, istihadah and nifas apart is, by necessity, also logging when you are and are not praying and fasting. That combination says more about your religious practice than either fact says on its own, which is exactly the kind of inference the checklist above exists to catch before it happens rather than after. The stakes are sharper still during Ramadan specifically, when what you log ties directly to a running record of missed and made up fasts.

If Flo specifically is the one you are reconsidering, see how the best Flo alternative for Muslim women actually compares against this same checklist.

Nisaa does not sell your personal information, keeps your cycle and health data out of the analytics and advertising tools used elsewhere in the app, stores it encrypted, and lets you delete it on request. None of that is asked to be taken on faith: it is set out in the privacy policy, not only in marketing copy. If that is the bar you are checking a tracker against, Nisaa is on the App Store.