AI That Never Leaves Your Phone
Your personal AI assistant that runs entirely on your device. No internet. No cloud. No account. Just powerful, private AI.
Everything you need.
Nothing you don't.
Powerful AI that respects your privacy, works without internet, and costs nothing per month.
Works Offline
Download an AI model once, then chat anytime — on a plane, in the subway, or off the grid. No internet required.
100% Private
Your conversations never leave your device. No servers, no analytics on your chats, no account. Your words stay yours.
15+ AI Models
Llama, Gemma, Qwen, Mistral and more. From tiny & fast to large & powerful — pick the right model for the job.
Your Language
Dedicated models fine-tuned for Turkish, Japanese, Korean, Chinese, Arabic, German, French, Spanish & Russian.
Real Conversations
Streaming responses, Markdown rendering, code blocks, 6 AI personas — everything a modern AI chat should have.
Connect Your PC
Run bigger models on your computer with Ollama or LM Studio, and chat from your phone over local Wi-Fi.
Up and running in 3 minutes
No signup, no configuration, no technical knowledge needed.
Download Cortis
Free from the App Store or Google Play. No account required — just open and go.
Pick a Model
Choose from 3 free AI models. Cortis recommends the best one for your device automatically.
Chat Anywhere
That's it. Chat with your AI — even in Airplane Mode. No internet needed ever again.
Your conversations are
yours alone
Unlike cloud AI services, Cortis never sends your data anywhere. Not now, not ever.
No Cloud Servers
All AI processing happens on your phone's processor. Your text never touches the internet.
No Account Required
No email, no login, no signup. Download and start chatting immediately.
You Control Analytics
Optional, minimal analytics to improve the app — you choose. Your conversations are never collected, period.
Local Storage Only
Chat history is saved in a local database on your device. Delete it anytime — it's your data.
No subscription. Ever.
Start free. If you love it, upgrade once — keep forever.
| Service | Price | Privacy | Offline |
|---|---|---|---|
| ChatGPT Plus | $240/year | Data collected | No |
| Claude Pro | $240/year | Data collected | No |
| Gemini Advanced | $240/year | Data collected | No |
| ⚡ Cortis Pro | $4.99 once | Zero data | 100% offline |
| ⚡ Cortis Free | Free | Zero data | 100% offline |
Start chatting.
Completely private.
3 free AI models. No account. No internet needed.
Questions? Answers.
Does it really work without internet?
Yes, 100%. After you download an AI model (which needs internet once), you can chat completely offline. Turn on Airplane Mode and try it — it works!
How good are the AI responses compared to ChatGPT?
On-device models are smaller than ChatGPT's server-side models, so they're great for everyday tasks (writing, questions, brainstorming, coding help) but won't match GPT-4's performance on complex reasoning. The trade-off is privacy and offline access — and for most daily use, the quality is impressive.
Which phones can run this?
iPhone 12 or newer works great. On Android, you need at least 4 GB of RAM. The smallest model (Llama 1B) runs on almost any modern phone. Bigger models need flagship devices with 6-8 GB RAM.
Is my data really private?
Yes. AI runs 100% on your device — your conversations never leave your phone. We include optional, minimal analytics and crash reporting to improve the app, and you control this from settings. The only network calls are: downloading models, purchase verification via Apple/Google, and optional app updates.
What's the difference between Free and Pro?
Free gives you 3 AI models and unlimited chatting — no time limit, no message cap. Pro ($4.99 launch price) unlocks 12+ additional models including larger, more capable ones and language-specific models for 9 languages, plus advanced controls and the ability to connect to your computer's AI setup.
How much storage do models need?
The smallest model is about 750 MB. Larger models range from 1.5 GB to 5.5 GB. You can download and delete models freely — they're stored like any other file on your phone.
Built with ❤️ by a solo developer