private-diary: A Fully Offline Calendar-Style Private Journal for Android and PWA

⚡ The Gist in 5 Seconds - wxk66/private-diary is a fully offline calendar-based journal: data stays on the device, with no network or account needed. - Available as a PWA for mobile browsers and as an installable Android APK. - Limitation: the authors stress that it's not a medical tool, but a personal journal for self-observation. ### 🔍 What Was Found The wxk66/private-diary repository hosts " " (Private Diary) — a calendar-based diary with a timer, statistics, and local storage. The current Android build is private-diary-v1.3.0.apk, about 93 KB; it's available in Releases and in app/android/dist. The PWA runs at https://wxk66.github.io/private-diary/ and can be added to the browser's home screen; once installed, it opens in its own window and works offline. The interface is bilingual: Chinese and English, with instant switching. There's a calendar with 42 cells, color-coded indication of entry counts (levels 1–4, a number for more than 4), a timer on the main screen, time autofill, and long-press entry creation. Statistics cover the last 30 days, 12 months, a 26-week heatmap, types and triggers, and 14 metrics. The PIN is 4 digits: the password is stored as PBKDF2-SHA256 with 120,000 iterations and a random salt, and after five failed attempts there's a lockout with doubling wait times. The APK includes fingerprint unlock: only if a scanner, enrolled fingerprints, and a screen lock are present. ### 💡 Why It Matters The key point is full autonomy. The app makes no network requests, there's no fetch or XMLHttpRequest in the code, the APK doesn't request network or storage access, and the only permissions are notifications, autostart after reboot, and the fingerprint scanner. Data lives in localStorage, so clearing the browser deletes entries; JSON export and import are provided. It's a practical option for a private journal with no clouds, accounts, or telemetry. The APK additionally uses AlarmManager: the daily reminder fires even when the app is closed and is restored after a reboot. ### 🧩 Context The authors deliberately avoid calling the app medical. The default limits — "3 times a week" and "10 times a month" — are a personal goal, not a norm: there is no single standard for frequency. Continuous streaks and nighttime entries (0:00–5:00) are considered more telling, while what matters clinically is the impact on sleep, work, and emotions, the inability to stop, and physical discomfort. Data is stored in localStorage under the key private-diary.v1, and entries from dyf.tracker.v1 are migrated automatically. If the condition interferes with daily life, the developer advises discussing it with a doctor or psychologist.

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