OpenMessage

OpenMessage is a local-first messaging workspace for Google Messages, WhatsApp, and Signal. Use it from the native macOS app, the localhost web UI, or any MCP-compatible client.

Built on mautrix/gmessages (libgm) for the Google Messages protocol and mcp-go for the MCP server.

What it does

• Google Messages for Mac — pair your Android phone and read/send SMS + RCS locally
• Live WhatsApp support — link WhatsApp as a live companion device on your machine
• Live Signal support — link Signal locally and keep its threads in the same inbox
• One local inbox — search, route-aware threads, favorites, media, reactions, drafts, scheduled sends, and grouped contacts
• Rich compose — text, media, GIFs, drag/drop attachments, link previews, replies, forwards, and browser-side queued sends while a route reconnects
• macOS app + PWA web UI — native wrapper with notifications and contact photos, plus an installable localhost UI
• MCP-ready — expose the same local inbox to Claude Code and other MCP clients over stdio, Streamable HTTP, or SSE

Quick start

Prerequisites

• Go 1.22+ (install)
• Google Messages on your Android phone

1. Clone and build

git clone https://github.com/MaxGhenis/openmessage.git
cd openmessage
go build -o openmessage .

2. Pair with your phone

OpenMessage uses Google Account pairing with emoji confirmation. QR setup is no longer supported: Google documents that QR pairing is unavailable in the US, and the upstream transport retired QR login.

On your phone, open Google Messages > Account menu > Device pairing and sign in to your Google Account. On your computer, open Messages for web and sign in to the same account.

For the CLI on any platform:

1. In the browser's developer tools, open Network, select a request to messages.google.com with a Cookie request header, and copy that header's value (or Copy as cURL if it includes a Cookie header).
2. Run:

   ./openmessage pair --google
   

3. Paste the cookies, then send end-of-input: Ctrl-D on macOS/Linux, or Ctrl-Z then Enter on Windows. Tap the matching emoji in Google Messages on your phone when prompted.

The CLI also accepts a JSON object of cookie names and values through stdin or --google-file path. Treat this input as a credential; keep it local. The session saves to ~/.local/share/openmessage/session.json by default, or OPENMESSAGES_DATA_DIR when set.

On macOS, you can instead read cookies from a signed-in Chrome profile:

./openmessage pair --google-chrome             # Default profile
./openmessage pair --google-chrome "Profile 1" # Another profile

The native macOS app offers Google sign-in and an advanced cookie-paste method. If embedded sign-in fails, use the advanced method. Running bare openmessage pair prints account-pairing instructions before opening a connection or changing a session.

3. Start the server

./openmessage serve

This starts the Web UI at http://127.0.0.1:7007. A bare serve is web-only.

MCP transports require an explicit opt-in:

• ./openmessage serve --mcp-sse starts MCP Streamable HTTP and SSE without the web UI.
• ./openmessage serve --web --mcp-sse starts the web UI and both HTTP MCP endpoints.
• ./openmessage serve --mcp-stdio starts MCP over stdio for pipe-based clients.

3a. Optional: link WhatsApp or Signal

After serve is running, open the local UI and link WhatsApp or Signal from the Connections surface. OpenMessage keeps those bridges local and syncs them into the same inbox as Google Messages.

3b. Safe demo mode for screenshots and recordings

./openmessage demo

or:

./openmessage serve --demo

Demo mode starts the same local UI on the normal port, but:

• uses a fresh temporary data directory instead of your real message store
• seeds fake SMS and WhatsApp conversations for screenshots and demos
• disables live Google Messages, WhatsApp, and local desktop import sync

This is the safest way to capture website screenshots, App Store assets, or demo recordings without real messages bleeding back in.

4. Connect to Claude Code

Add to ~/.mcp.json:

{
  "mcpServers": {
    "openmessage": {
      "command": "/path/to/openmessage",
      "args": ["serve", "--mcp-stdio"]
    }
  }
}

Restart Claude Code. The MCP tools appear automatically.

To let a client connect over HTTP, start OpenMessage with --mcp-sse (or --web --mcp-sse to keep the web UI), then point it at:

• Streamable HTTP: http://127.0.0.1:7007/mcp
• SSE: http://127.0.0.1:7007/mcp/sse

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