Kai

<img src="https://img.shields.io/badge/Platform-Web-f7df1c?logo=javascript" alt="Web"> <img src="https://img.shields.io/badge/Platform-Android-34a853.svg?logo=android" alt="Android" /> <img src="https://img.shields.io/badge/Platform-iOS-lightgrey.svg?logo=apple" alt="iOS" /> <img src="https://img.shields.io/badge/Platform-Windows/macOS/Linux-e10707.svg?logo=openjdk" alt="Platform JVM" />

An open-source AI assistant with persistent memory that runs on Android, iOS, Windows, Mac, Linux, and Web.

Documentation

Installation

Homebrew (macOS):

brew install --cask simonschubert/tap/kai

AUR (Arch Linux):

yay -S kai-bin

Winget (Windows):

winget install SimonSchubert.Kai

Direct Downloads

Features

• Persistent memory — Kai remembers important details across conversations and uses them automatically
• Customizable soul — Define the AI's personality and behavior with an editable system prompt
• Multi-service fallback — 17 LLM providers with automatic failover
• Tool execution — Web search, notifications, calendar events, shell commands, and more
• MCP server support — Connect to remote tool servers via the Model Context Protocol
• Autonomous heartbeat — Periodic self-checks that surface anything needing attention
• Settings export/import — Backup and restore all settings as a JSON file
• Encrypted storage — Conversations stored locally with encryption
• Text to speech — Listen to AI responses
• Linux Sandbox — On Android, the AI can run shell commands, scripts, and tools in a secure sandboxed Linux environment
• Image attachments — Attach images to any conversation

Linux Sandbox (Android)

On Android, Kai includes a built-in Linux environment that the AI can use to execute shell commands, run scripts, and operate tools on your behalf. This turns Kai from a chat-only assistant into one that can take real action — installing packages, processing data, running Python scripts, and more.

• Powered by Alpine Linux — A lightweight ~3 MB download sets up a full Linux userland via proot, no root required
• Optional packages — One tap installs bash, curl, wget, git, jq, python3, pip, and Node.js
• Interactive terminal — A built-in terminal lets you run commands manually alongside the AI
• Secure — Everything runs sandboxed inside the app with no access to the host system

Enable it in Settings > Linux Sandbox.

Screenshots

Desktop

Web

Mobile

<img src="screenshots/mobile-1.png" alt="Mobile Screenshot 1" height="300"> <img src="screenshots/mobile-2.png" alt="Mobile Screenshot 2" height="300"> <img src="screenshots/mobile-3.png" alt="Mobile Screenshot 3" height="300"> <img src="screenshots/mobile-4.png" alt="Mobile Screenshot 4" height="300"> <img src="screenshots/mobile-5.png" alt="Mobile Screenshot 5" height="300"> <img src="screenshots/mobile-6.png" alt="Mobile Screenshot 6" height="300">

How It Works

                        ┌────────┐
                        │  User  │
                        └───┬────┘
                            │ message
                            ▼
               ┌─────────────────────────┐
               │          Chat           │
               │                         │
               │  prompt + memories      │
               │        │                │
               │        ▼                │
               │    ┌────────┐           │
               │    │   AI   │◀─┐        │
               │    └───┬────┘  │        │
               │        │   tool calls   │
               │        │   & results    │
               │        ▼      │        │
               │    ┌────────┐ │        │
               │    │ Tools  │─┘        │
               │    └───┬────┘          │
               │        │               │
               └────────┼───────────────┘
                        │ store / recall
                        ▼
               ┌─────────────────┐    hitCount >= 5
               │     Memory      │───────────────────┐
               │                 │                   │
               │  facts, prefs,  │                   ▼
               │  learnings      │          ┌────────────────┐
               │                 │◀─delete──│ Promote into   │
               └─────────────────┘          │ System Prompt  │
                        ▲                   └────────────────┘
                        │ reviews
                        │
               ┌─────────────────┐
               │    Heartbeat    │
               │                 │
               │  autonomous     │
               │  self-check     │
               │  every 30 min   │
               │  (8am–10pm)     │
               │                 │
               │  all good?      │
               │  → stays silent │
               │  needs action?  │
               │  → notifies user│
               └─────────────────┘

• Chat — User sends a message. The AI responds, calling tools (memory, web search, shell, etc.) in a loop until it has a final answer.
• Memory — The AI stores and recalls facts, preferences, and learnings. Memories that prove useful (5+ hits) can be promoted into the system prompt permanently.
• Heartbeat — A background self-check runs every 30 minutes. It reviews memories, pending tasks, and emails. If something needs attention, it notifies the user. Otherwise, it stays silent.

Supported Services

Plus a built-in Free tier that requires no API key.

MCP Servers

Kai supports the Model Context Protocol for connecting to external tool servers. Go to Settings > Tools > Add MCP Server to connect to any Streamable HTTP MCP endpoint, or pick from a curated list of popular free servers:

All popular servers are free and require no API key. MCP servers auto-reconnect on app startup.

Integrations

Splinterlands Auto-Battle (Android & Desktop)

Kai can automatically play Splinterlands Wild Ranked battles. Configure one or more LLM services in priority order, add your Hive account, and hit Start -- Kai will continuously find matches, pick teams using LLM-powered strategy, and submit them on-chain. Falls back to a simple greedy picker if all LLM services fail. Available in Settings > Integrations.

Supported Languages

Afrikaans, Albanian, Amharic, Arabic, Belarusian, Bengali, Bulgarian, Chinese (Simplified), Chinese (Traditional), Croatian, Czech, Danish, Dutch, English, Estonian, Filipino, Finnish, French, German, Greek, Gujarati, Hebrew, Hindi, Hungarian, Indonesian, Italian, Japanese, Kazakh, Korean, Latvian, Lithuanian, Malay, Marathi, Norwegian, Persian, Polish, Portuguese, Punjabi, Romanian, Romansh, Russian, Serbian, Slovak, Slovenian, Spanish, Swahili, Swedish, Tamil, Telugu, Thai, Turkish, Ukrainian, Urdu, Vietnamese, Zulu

Contributing

Screenshot Automation

Two separate screenshot pipelines exist, both using Compose screenshot tests:

README screenshots — Used for this README. CI runs this automatically on every push and auto-commits any changes.

./gradlew :screenshotTests:updateScreenshots

Store screenshots — Generates localized screenshots for the Play Store in all supported locales. Upload via fastlane.

./gradlew :screenshotTests:generateStoreScreenshots
bundle exec fastlane android upload_screenshots

Sponsors

This project is open-source and maintained by a single developer. If you find this app useful, please consider sponsoring to help take it to the next level with more features and faster updates.

Credits

• Lottie animation: https://lottiefiles.com/free-animation/loading-wDUukARCPj
• Mistral: https://mistral.ai/