The first AI journal with an on-device LLM. Military-grade encryption meets sovereign intelligence — your thoughts never leave your phone.
We didn't just build a journal. We built a vault for your consciousness.
Your 6-word recovery phrase generates all encryption keys via Argon2id. We never see them. We can't decrypt your data — even if compelled by law.
A full language model running entirely on your phone — 1B parameters for mid-range devices, 3B for flagship. Reflections, summaries, and pattern analysis without a single byte leaving your device.
Whisper-powered transcription runs entirely on your device. Speak your mind without it ever touching a server.
Correlate journal entries with sleep, heart rate, steps, and workout data from Health Connect. All processing stays local — your health data never leaves your device.
Military-grade encryption with Argon2id key derivation (64MB memory, 3 iterations). Hardware-backed key storage (iOS Secure Enclave / Android Keystore), 12-byte IV, 128-bit authentication tags. Every entry is encrypted before storage.
Optional encrypted cloud backup where even our servers only see encrypted blobs. Automatic sync, end-to-end encrypted, with per-user derived keys.
Not all journals are created equal.
CortexOS runs Meta's Llama 3.2 directly on your device. No cloud APIs, no data exfiltration, no subscriptions to external AI services. Your journal is analyzed by an AI that physically cannot leak your thoughts.
1B parameters (700MB) for mid-range devices, 3B parameters (1.8GB) for flagship phones. Auto-detected based on your hardware.
AI-generated weekly reflections, chapter summaries, and personalized journaling prompts — all computed locally.
Discovers connections between your mood, sleep, activities, and health data. Surfaces insights you'd never find on your own.
The model runs in-process on your device. No network calls, no cloud inference. Your thoughts literally cannot leave your phone.
A complete mental wellness toolkit, entirely private.
Format your thoughts with markdown, headings, and lists. Your journal, your style.
Speak your mind. Auto-transcribed locally with OpenAI's Whisper model — never uploaded.
Beyond basic mood tracking — detects joy, love, hope, gratitude, pride, anxiety, anger, fear, sadness, and 6 more nuanced emotions.
Write "remind me tomorrow at 3pm" in any entry and CortexOS automatically detects and schedules it. No extra steps.
Start journaling instantly from your home screen. Quick-capture your thoughts without opening the full app.
Real-time mood tracking within a journaling session. Detects sudden emotional drops and offers supportive check-ins.
7-day narrative chapters with AI-generated names. Track your streak, earn milestones, and watch your story unfold.
The AI learns your unique writing style over time. Topic-sentiment offsets adapt to how you personally express emotions.
Discover how sleep, heart rate, steps, and workouts affect your mood. All computed on-device via Health Connect.
Organize with tags. Find any entry instantly with search — all within your encrypted vault.
Your data belongs to you. Export as JSON, PDF, or plain text anytime.
Fingerprint or face unlock. Quick access with maximum security.
Three tiers of on-device AI analysis. All private, all local.
Essential insights for daily journaling
Full AI power with on-device LLM
Same as Deep — pay once, own forever
14-day free trial included with Cortex Deep. Cancel anytime — no charge if you cancel within the trial period.
Jan 15 - Jan 21, 2025
Jan 1 - Jan 7 • Completed
Jan 8 - Jan 14 • Completed
Journey & Chapters
Your journal entries aren't just data points — they're chapters in your story. CortexOS automatically groups your entries into 7-day narrative chapters with AI-generated names based on your dominant themes and emotions.
7 consecutive days of journaling completes a chapter with a unique, AI-generated name.
Track your streak with satisfying progress bars. Watch your story grow day by day.
Complete a chapter and receive personalized celebration messages and insights.
Four layers of protection for your most private thoughts.
Your recovery phrase derives all encryption keys using Argon2id — 64MB memory-hard hashing, 3 iterations, 4 parallel lanes. No shortcuts, no backdoors, no key escrow.
Every entry, voice note, and attachment is encrypted with AES-256-GCM before it touches storage. Hardware-backed key storage (iOS Secure Enclave / Android Keystore) with 12-byte IV and 128-bit authentication tags.
Llama 3.2 LLM, TensorFlow Lite sentiment analysis, and Whisper transcription all run in-process on your device. Zero network calls for AI — your thoughts physically cannot be exfiltrated.
Optional cloud backup encrypts everything client-side before upload. Our servers store encrypted blobs — we cannot decrypt them. Per-user derived keys with canary verification.
"We built CortexOS because we wanted a journal we'd actually trust with our own thoughts."— The CortexOS Team
CortexOS is coming soon to iOS & Android. Join the waitlist and we'll notify you at launch.
Coming soon on iOS & Android