A self-hosted, open-source chat application where every conversation is a git repo, every message is a commit, and forking a conversation creates a git branch.

Built with Next.js and powered by Claude API.

GitChat treats conversations like code — with full version control. Instead of a flat message history, each conversation is a local git repository:

• Messages are commits — every user message and AI response is stored as a git commit
• Branches are conversation paths — fork any conversation at any point to explore a different direction
• The tree is your map — an interactive sidebar visualizes all branches, letting you navigate your conversation's history

This means you can:

• Ask the same question and get different answers (regenerate)
• Branch off an AI response to explore a tangent
• Delete a dead-end and keep going from where things were good
• See every path you've explored in a visual tree

• Node.js 18+
• Git installed and available in PATH
• An Anthropic API key from console.anthropic.com

# Clone the repo
git clone https://github.com/your-username/gitchat.git
cd gitchat

# Install dependencies
npm install

# Configure your API key
cp .env.example .env.local
# Edit .env.local and add your ANTHROPIC_API_KEY

# Start the dev server
npm run dev

Open http://localhost:1129 to start chatting.

Send messages and receive streaming AI responses in real-time. The full conversation history of the active branch is always sent as context, so Claude remembers everything from that conversation path.

Fork from any AI response to write a different follow-up question. The new branch inherits the full conversation history up to that point.

Regenerate from any user message to get a different AI answer. Click the regenerate button (or pick a character persona from the dropdown) and a new branch is created from your question with a fresh AI response streamed in real-time.

Branch names are auto-generated as memorable two-word combos (e.g. azure-dolphin, quiet-zebra) and can be renamed at any time.

The sidebar shows your entire conversation as an interactive tree graph:

• User nodes (blue) and AI nodes (purple) connected by edges
• Pan and zoom to navigate large conversation trees
• Hover any node to preview its content
• Click to jump to that message in the chat
• Search across all branches to find and highlight matching messages
• Delete a message node to remove it and everything after it (with cascade confirmation)

The tree panel is collapsible and resizable — drag the divider or toggle it with the tree button in the header.

Create custom AI personas that modify how Claude responds during regeneration:

• Default characters: Philosopher and Physicist are included out of the box
• Custom characters: Create your own with a name and description (system prompt modifier)
• AI prompt helper: Click "Help from AI" when creating a character — describe the concept in plain language and Claude generates a proper system prompt for you
• Editable: Click any character to expand and edit its description inline
• Per-conversation: Enable or disable characters for each conversation with a toggle switch — only enabled characters appear in the regenerate dropdown
• Auto-inheritance: Once you regenerate with a character, all follow-up messages on that branch automatically continue in that character's persona
• Tree tags: AI responses generated with a character show a purple name tag on their tree node, so you can see which branches are "in character"
• Quick access: The regenerate dropdown shows all enabled characters for one-click selection

Characters are stored globally in data/characters.json and managed from the character panel in the conversation sidebar.

• Create new conversations from the home page
• Rename conversations inline from the conversation list
• Delete conversations permanently (removes the entire git repo)
• Switch branches via the branch selector dropdown with rename support

Delete messages from any point in a conversation:

• A small × button appears on user message nodes in the tree on hover
• AI answer nodes can also be deleted when there are multiple answers from the same user message (from regeneration)
• Deletion is destructive (git reset --hard) — the messages are permanently removed
• Cascade delete: any branches forked from the deleted messages are also removed
• A confirmation dialog shows exactly what will be affected before proceeding

data/
├── conversations/
│   └── <uuid>/                    # Each conversation is a git repo
│       ├── .git/                  # Git internals
│       ├── conversation.json      # Metadata (title, createdAt)
│       ├── .character-config.json # Per-conversation character settings
│       └── messages/
│           ├── 2026-03-22T10-00-00-user.md
│           ├── 2026-03-22T10-00-01-assistant.md
│           └── ...
└── characters.json                # Global character definitions

• Framework: Next.js 14 (App Router)
• UI: React 18 + Tailwind CSS
• AI: Anthropic Claude API with SSE streaming
• Storage: Git (no database — git is the database)
• Markdown: react-markdown with remark-gfm
• Branch Names: unique-names-generator

• No database — every piece of data is either a git commit, a git branch, or a JSON file
• Full context — the AI always receives the complete conversation history from root to branch tip
• Streaming everywhere — both normal chat and regeneration stream tokens in real-time via Server-Sent Events
• Destructive deletes — when you delete, it's gone (git reset --hard). The tree visualization makes it clear what you're removing

npm run dev    # Start development server
npm run build  # Build for production
npm run start  # Start production server
npm run lint   # Run ESLint
npm test       # Run tests

Open source. Self-hosted. Your conversations stay on your machine.