// the find
getify/youperiod.app
YouPeriod.app -- the privacy-first period tracking app
A PWA for period tracking that stores all data locally on-device, encrypted, with no server sync or account required. Built by Kyle Simpson (getify, of 'You Don't Know JS' fame), so the JavaScript is serious. The target audience is people who want health tracking with zero data exposure risk.
Uses Argon2 for key derivation and Web Crypto for encryption — not a hand-rolled toy crypto scheme. PWA-offline-first design means it genuinely works without a server after install, which matches the threat model. Open-source and auditable, which is the only real guarantee for a privacy claim. The passphrase wordlist approach to auth is a thoughtful UX choice that avoids the usual password recovery problem.
The README still says 'not ready for use yet' and the last commit was September 2023 — this appears abandoned before reaching production quality. No backup or data export mechanism is described, which is a serious problem for medical data: lose your device, lose everything. No test suite visible in the tree. The encryption is client-side JS, which is only as safe as the server you loaded the JS from — a detail the app doesn't address beyond 'once installed, runs offline'.