
CortexOS - Zero-Knowledge AI Journal
Your mind, encrypted. AI that never leaves your phone.
4 followers
Your mind, encrypted. AI that never leaves your phone.
4 followers
Every AI journal sends your thoughts to a server. CortexOS doesn't. A full LLM (Llama 3.2) runs entirely on your phone. Voice transcription, 20+ emotions, 15 distortions, AI reflections, emotional chapters, yearly review. All on-device. All encrypted. Offline or online. Your entries are locked behind a 6-word phrase and PIN only you know. We can't read your data. Nobody can. That's not a setting. That's the architecture. New category: Zero-Knowledge AI Journal. Solo-built. 14-day free trial.








Hey everyone,
I'm Orlin, the creator of CortexOS.
I've always wanted to journal but never could bring myself to do it digitally. Not because I didn't want to. Because I didn't trust where my words would end up. Every app I tried stored my thoughts on someone else's server. And that never sat right with me. A diary is supposed to be the one thing that's truly yours. Like that notebook you kept under your pillow as a kid. Nobody read it because nobody could, because it was hidden. In the safest place you could hide it.
I wanted that. But with AI that actually helps you think.
So I built CortexOS with that idea. Your thoughts are not marketing data. They're yours and yours alone. And it deserves Zero-Knowledge Encryption - a true privacy architecture that makes reading your entries truly impossible.
Every feature came from a personal place:
I built Chapters because I wanted to look back at my life in organized periods. Seven days of writing becomes one named chapter. After a year you have 52. Your emotional autobiography.
I built Reflections because sometimes you need five minutes to dump everything in your head. No filter. Just you and an AI that asks the right questions and helps you reframe the mess.
I built the Yearly Review because we let entire years blur together and forget the details that mattered.
I built it on-device because a diary that lives on a server isn't a diary. It's a liability.
The app was almost finished when I got fired in January. Two weeks later my brain ruptured. Aneurysm. Surgery. The guy who built a journal because he was scared of losing his memory almost lost the whole thing. Life's got jokes.
Back on my feet in three weeks. Finished the app. It's live now.
This is v1.0. A lot more is coming. But it works and it does what I say it does.
If you're curious about how the zero-knowledge encryption actually works under the hood, I've got the crypto layer open source on GitHub and a full whitepaper. Just drop me a line and I'll share.
Happy to answer any questions regarding CortexOS!