CortexOS

CortexOS is the zero-knowledge AI journal. Write or speak. A real language model on your phone (not in the cloud) reads what you wrote, picks up your emotions, and reflects what you'd miss. Nothing leaves the device. Ever.

iOS and Android, full feature parity.

What makes CortexOS different from other AI journals

Most AI journals send your content to a cloud LLM. The privacy guarantee is contractual ("we don't train on your data"). Your content still leaves your device every time you use the AI.

CortexOS does the AI on your phone. The language model runs in the app's own process. Your entry text is never transmitted for AI inference. The encryption is unconditional, derived from a six-word recovery phrase only you hold, with no path back through account recovery.

The cryptographic core is open source under MIT on GitHub for independent audit.

An AI that learns you

Most journaling apps treat every entry like your first. CortexOS keeps a quiet, private picture of you on your phone: what you've been working through, the themes that come up, the thinking patterns that trip you up, the threads you haven't finished. Every reflection gets sharper the longer you write.

Features

• Deep Analysis — On-device AI reads between the lines, surfacing emotional patterns, thinking habits, and growth you'd miss yourself.
• Behavioral Patterns — Rumination, self-compassion, stress responses, growth moments. Nothing diagnosed. Just named.
• Self-Awareness Card — A running picture of your themes, tendencies, habits, and growth. Built from your own words.
• AI Reflections — Talk through what's on your mind with a private AI companion, by text or voice. It remembers your themes.
• Standard or Enhanced — Pick the AI that fits your phone. Switch any time in Settings.
• Voice Journaling — Transcription runs on your device. No audio touches a server.
• Insights & Patterns — 20+ emotions tracked over days, weeks, months. Trends, triggers, connections.
• Chapters & Year in Review — Every week becomes an auto-titled chapter. Once a year, your entries become a story of the year you lived.
• Smart Notifications — Prompts shaped by what you've been writing. Tapping a notification requires biometric unlock or your PIN.
• Therapist Reports — A shareable PDF of your emotional patterns. No journal content.

Private by design

Same encryption banks and governments use, applied on your phone. Zero-knowledge cloud backup we cannot read. On-device AI, nothing sent to servers. A six-word recovery phrase is the only key. Biometric and PIN lock. Cryptographic core open source under MIT. EU AI Act Limited Risk compliant. No tracking. No ads.

• Website: https://cortexos.app
• Crypto core: https://github.com/CortexOS-HQ/CortexOS-crypto-core

Built by a solo founder in Malta. No investors, no ads, no data deals. Your Mind, Encrypted.