CortexOS

CortexOS is a zero-knowledge AI journaling app for iOS and Android. Its core idea: a real language model, Llama 3.2, reads and reflects on your journal entries directly on your phone. No data ever leaves the device. There are no cloud calls, no third-party AI services, and no external servers. The encryption code is open source under an MIT license on GitHub, so users can independently verify that entries remain inaccessible to anyone, including the developers.

Every entry receives a written reflection that summarizes what you wrote in your own voice, identifies cognitive patterns with suggested reframes, and links to past entries with similar themes. Paid tiers unlock Deep Analysis, which runs after each entry and produces a detailed reflection within seconds. The AI tracks emotional states (over 20 emotions on premium tiers) and behavioral patterns, and builds an encrypted personal summary that updates with each entry. Users can choose between a standard or enhanced AI model (roughly 1 GB or 2 GB) and switch at any time.

The typical workflow is simple: write daily or occasional entries, then receive reflections that surface recurring themes, emotional trajectories, and connections to older entries. Nudges and prompts are shaped by your actual emotional history. The free tier includes ten encrypted entries per month, voice journaling, and basic emotion detection. Premium tiers (7-day free trial) add full AI capabilities, deeper emotional analysis, pattern detection, and an encrypted cloud vault for backup. A lifetime purchase is also available.

Technically, everything runs on-device: the model executes in the app's own process with no network calls, and encryption keys are derived from a recovery phrase, making it impossible for anyone else to read the entries.