Cortis: Private AI Chat

Cortis: Private AI Chat puts a personal AI assistant directly on your phone and runs entirely offline so you do not need an account or cloud servers. Download a model once and continue conversations in airplane mode, on the subway, or anywhere without internet, while every chat remains stored locally. The app is designed for users who prioritize privacy, straightforward setup and multilingual capability, offering several modern models and task-focused personas for writing, coding, tutoring and research without sending your data to external servers.

Key Features

Run AI locally by downloading models to your device and using them offline, including in airplane mode. True on-device privacy means conversations stay on your phone with no analytics or tracking sent to cloud servers. Choose from 15+ models, including popular open weights and language-optimized variants for multiple regions. The app provides real-time streaming responses, full Markdown support for code blocks, lists and tables, and multiple AI personas tailored to different tasks. Local conversation history is saved on-device so you can review past chats without cloud backups. Pro users can connect to a desktop host over the local network to access much larger models (70B+).

Benefits

Cortis: Private AI Chat keeps your conversations private by processing everything locally and avoiding external data transfers. Offline capability makes the app reliable for travel and commutes where internet access is limited. There is no ongoing subscription model: the app includes three free models to start and offers an optional one-time upgrade to Cortis Pro for access to additional features. Dedicated models optimized for languages such as Turkish, Chinese, Japanese, Korean, Arabic, German, French, Spanish and Russian provide better native-level handling than simple translation.

Considerations

Downloaded AI models require local storage and may occupy a noticeable amount of space depending on model size. Access to the largest 70B+ models requires a local desktop host and the Pro feature. Performance and responsiveness depend on your phone’s hardware capabilities, so older devices may experience limitations with heavier models.

About the developer

The app was built by an independent developer focused on privacy and accessibility: Cortis: Private AI Chat reflects a clear stance against data farming and aims to deliver affordable, private AI tools for everyday use without venture capital involvement.