Mood Cairns

A private, fully offline Android mood tracker. Log how you're feeling against your own Scales, with your own Tags, in your own time windows, on your own device. Nothing is ever uploaded - backup, if you want it, is done your own way (hint: Syncthing works well on the encrypted backups you save.).

Features

* Custom Scales. Five built-in scales (Happiness, Anxiety, Stress, Boredom, Pain), each numeric and color-tagged. Add your own; archive the ones you don't want.
* Custom Tags. Choose from many built-in Tags for Places, People, Activities, Moods, etc. or add your own to customize your tracking!
* Prompt windows. Define time-of-day windows (e.g. morning 08:00-12:00, evening 18:00-20:00). The app fires one notification per window per day. Tap the notification to jump straight to the log entry screen.
* History and charts. Browse past entries, see per-scale trends over time.
* Encrypted on-disk storage. The mood database is encrypted at rest using SQLCipher. The key lives in memory only while the app is unlocked, and is wiped when you lock it.
* PIN + biometric lock. PIN-gated app entry, with optional biometric unlock. PIN is hashed with PBKDF2-HMAC-SHA256 (600k iterations) before being stored.
* Encrypted backups. Manual export writes an AES-GCM-encrypted JSON file to Documents/MoodCairns/. The encryption key is derived from your PIN with PBKDF2-HMAC-SHA256 (200k iterations) and a fresh per-backup salt embedded in the envelope, so any install (including a fresh one) can decrypt with the same PIN.

Privacy contract

The app declares no network permissions. Without internet, the process literally cannot open a socket, which makes phone-home impossible regardless of what any included library tries to do.
The build enforces this, so a network permission can never be silently introduced by a dependency update.
If you want backups synced off-device, point Syncthing (or any file manager that can sync a folder) at Documents/MoodCairns/.

Contact

The best way to get in touch for issues, feature requests, etc. is the Issues page on github.com/lcdcode/mood-cairns. I will usually respond within 3 business days.

Source

Fully open source under GPL-3.0-only. Built on Kotlin, Jetpack Compose, Room, SQLCipher, and AndroidX.