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

Related MCP server: WAHA MCP

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 pair

By default, a QR code appears in your terminal. On your phone, open Google Messages > Settings > Device pairing > Pair a device and scan it. The session saves to ~/.local/share/openmessage/session.json.

If Google only offers account pairing, you can also pair with Google account cookies copied from browser devtools:

pbpaste | ./openmessage pair --google

The CLI accepts either a JSON cookie object or a full curl command for messages.google.com/web/config, then prompts you to confirm an emoji on your phone.

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

Features

• Read messages — full conversation history, search, media, replies, reactions, and route-aware conversation previews

• Send messages — SMS/RCS plus live WhatsApp and Signal text, media, reactions, replies, forwards, and send-later scheduling

• Queued compose — browser-side pending sends keep text and attachment previews visible while a route reconnects, then flush with idempotency keys to avoid duplicate sends

• GIF picker — Klipy-backed GIF search, preview proxying, favorites, captions, and media sends from the web composer

• Attachment workflow — upload, paste, drag/drop, preview, fullscreen viewing, PDFs, audio/video, and generic file cards

• Link previews — local preview/image proxying for message URLs with SSRF-safe URL validation

• Favorite threads — star important conversations and jump to them from the favorites rail

• Live WhatsApp sync — pair a local WhatsApp companion device for inbound messages, typing indicators, read state, and media

• Live Signal sync — pair a local Signal linked device for inbound messages, media, reactions, and group threads

• React to messages — emoji reactions on any message

• Image/media display — inline images, video, audio, and fullscreen viewer

• Contact workspace — grouped people across routes, contact metadata, tags, reach-out cadence, and relationship summaries

• Google repair flows — detects expired Google cookies, stuck sessions, and dead credentials, then offers guided reconnect or re-pair flows

• Desktop notifications — native macOS notifications for fresh inbound messages

• Web UI + macOS app — real-time conversation view at localhost:7007 and a native wrapper

• MCP tools — conversation lookup, route-aware text/media/reaction sends, media download, import helpers, and story/viz tools

• Local storage — SQLite database, your data stays on your machine

MCP tools

MCP examples

• List recent Signal threads: list_conversations(source_platform="signal")

• Search WhatsApp for a keyword: search_messages(query="airbnb")

• Send a direct Signal message: send_message(platform="signal", recipient="+15551230000", message="On my way")

• Send a text into a route-aware thread: send_to_conversation(conversation_id="whatsapp:15551234567@s.whatsapp.net", message="On my way")

• Send a photo from disk: send_media_to_conversation(conversation_id="signal-group:abc123", file_path="/tmp/photo.jpg", caption="Here")

• React to a message: react_to_message(conversation_id="signal-group:abc123", message_id="signal:...", emoji="🔥")

• Resolve a person's available routes before sending: resolve_contact_routes(query="Taylor")

• Review one person's cross-platform history: get_person_messages(name="Taylor", limit=50)

• Import Signal Desktop history: import_messages(source="signal", path="$HOME/Library/Application Support/Signal", name="Your Name", address="+15551230000")

Web UI

The web UI runs at http://localhost:7007 when the server is started. It provides:

• Conversation list with search and grouped multi-route contacts

• Message view with images, video, audio, reactions, and reply threads

• Favorites rail and thread-level shortcuts

• Route-aware compose, send, reply, forward, react, and send later

• GIF picker, emoji picker, media upload, drag/drop attachments, paste attachments, captions, and attachment previews

• Link previews and document/file cards

• Browser-side queued sends for temporarily disconnected routes

• Contact popovers, copied numbers, person-level summaries, tags, and reach-out cadence

• Google Messages + WhatsApp + Signal connection controls

• Google reconnect, cookie-expiry, and re-pair affordances

• Live typing indicators, read-state rendering, and notifications

Native macOS app

The repo also includes a native Swift wrapper around the same local backend:

• embedded local OpenMessage backend

• native notifications

• contact photos

• the same Google Messages, WhatsApp, and Signal pairing/runtime model as the web UI

The macOS app target lives under OpenMessage/.

Configuration

OPENMESSAGES_HOST defaults to localhost for safety. If you bind the server to another interface for LAN testing, keep it on a trusted network; local-control APIs and MCP endpoints are meant for same-origin/local clients.

GIF picker setup

The web compose GIF picker uses Klipy search. To enable it:

1. Create a Klipy API key.

2. Start OpenMessage with the key in the environment:

   export OPENMESSAGES_KLIPY_API_KEY=<your key>
   ./openmessage serve

3. Optional: verify the local endpoint can reach Klipy:

   curl "http://127.0.0.1:7007/api/gifs/trending?limit=1"

4. Open the web UI and use the GIF button in a media-capable conversation. GIF sends use the same media path as other attachments, so they are only enabled for routes that currently support media.

OpenMessage does not include a bundled GIF provider key. Without OPENMESSAGES_KLIPY_API_KEY, GIF search endpoints return a setup error and the rest of messaging continues to work normally.

If you launch OpenMessage from the macOS app, launchd, systemd, or another supervisor, configure the environment there too; exporting the key in a shell only affects serve processes started from that shell.

Architecture

• libgm handles the Google Messages protocol (pairing, encryption, long-polling)

• whatsmeow handles live WhatsApp pairing, sync, text/media send, receipts, typing, and avatars through a separate local session store

• signal-cli powers the local Signal linked-device bridge, message sync, media, and reactions

• SQLite (WAL mode, pure Go) stores messages, conversations, and contacts locally

• Real-time events from the phone are written to SQLite as they arrive

• The native macOS app and the localhost web UI run against the same local backend

• WhatsApp Desktop import remains as a fallback/repair path when the live bridge is not active

• Signal Desktop history can be imported into the same local store for backfill and repair workflows

• On first run, a deep backfill fetches full SMS/RCS history in the background; later runs do a lighter incremental sync by default

• Scheduled messages live in SQLite, are claimed atomically by the background scheduler, and retry when the target platform is temporarily disconnected

• The web composer stores pending browser-side sends in local storage/IndexedDB and attaches idempotency keys to prevent duplicate delivery during retry

• MCP tool handlers read from SQLite for queries and route sends through the same local runtime

• MCP HTTP transport supports both Streamable HTTP at /mcp and SSE at /mcp/sse when enabled with --mcp-sse; stdio is available with --mcp-stdio

• GIF and link-preview proxies validate remote URLs, cap downloads, and keep provider fetches inside the local backend

• Auth tokens auto-refresh and persist to session.json; expired Google cookies can be refreshed by an optional script or surfaced as a guided re-pair flow

Development

go test ./...        # Run all tests
go build .           # Build binary
npm install          # Install Playwright test runner
npx playwright install chromium
npm run test:e2e     # Run browser-level web UI tests
./openmessage pair  # Pair with phone
./openmessage serve # Start server
./openmessage demo  # Start isolated fake-data demo mode

Before publishing a build or website update, run through the release checklist.

Debugging a live install (failing sends, re-pairing, the two-data-dir gotcha, signal-cli version)? See docs/agent-runbook.md.

License

MIT