Which on-device period tracker is best for iPhone

For iPhone users, the on-device options are Floriva ($5.99/mo with encrypted sync) and Euki (free, no sync). Drip and Periodical are Android-only. If sync matters, Floriva is the only option. If cost matters, Euki is free.

Can any of these apps be subpoenaed

No. All four apps store data exclusively on your device. There are no company servers holding your data. A subpoena to any of these companies would produce nothing — the data doesn't exist on their infrastructure. Law enforcement would need physical access to your device or a warrant for your device, not a subpoena to the app company.

What is the most private period tracker

From a verifiability standpoint, Drip and Periodical are the most private because they're open-source — anyone can audit the code. From a practical standpoint, all four apps in this comparison achieve the same privacy outcome: no server data, no account, no subpoena surface. The choice between them is about features and platform, not privacy level.

comparisons

The Privacy-First Period Tracker Showdown: Floriva vs Euki vs Drip vs Periodical (2026)

The most private period trackers of 2026 compared. Floriva, Euki, Drip, and Periodical all store data on-device — here's how they differ on features, platforms, and tradeoffs.

Four period trackers have earned the right to call themselves private. Not because of privacy policies or compliance certifications — because of architecture. Floriva, Euki, Drip, and Periodical store your data on your device and nowhere else. No accounts. No servers. No data to subpoena, breach, or sell. This comparison is about the differences between them, because on privacy, they're all in the same category. The Shared Foundation Every app in this comparison passes the same fundamental test: if law enforcement serves a subpoena to the company, the company has nothing to produce. Your data is on your phone. The company doesn't have it. This is what zero knowledge architecture means in practice. This puts all four apps in a different category from cloud based trackers like Flo, Clue, Glow, Natural Cycles, or Ovia. The cloud vs local architecture comparison covers why this distinction matters. Floriva: The Cross Platform Option Floriva is the only on device tracker with both iOS and Android support and cross device encrypted sync. If you switch between an iPhone and an Android phone, or simply want your data preserved across device upgrades, Floriva handles that without storing da