whatsapp-mcp

Give your AI agents your WhatsApp.

whatsapp-mcp lets an AI assistant like Claude read your WhatsApp chats, search them and send messages for you. It connects to your account the same way WhatsApp Web does, as a linked device, and keeps a searchable copy of your chats.

It speaks MCP, the standard way AI apps connect to tools, so it works with Claude, ChatGPT, Claude Code, Cursor and other MCP clients. It runs on your own Cloudflare account, so your messages stay with you.

Once it is set up, you ask in plain words and your assistant calls the tools for you:

Get started

You need a Cloudflare account, a GitHub account and your phone with WhatsApp.

1. Deploy

Click Deploy to Cloudflare above. Cloudflare copies this project to your GitHub, builds it and puts it online at an address like https://whatsapp-mcp.<your-name>.workers.dev.

During the setup it asks for a SECRET. That is the password of your server, at least 16 characters. Generate a strong one in a terminal with openssl rand -hex 32, or use a password manager, and keep it safe. Anyone who has it can read and send your messages.

2. Link your WhatsApp

Open this address in your browser and sign in with your SECRET:

https://whatsapp-mcp.<your-name>.workers.dev/accounts/personal

Select Link WhatsApp. On your phone, open WhatsApp, go to Settings → Linked devices → Link a device and point the camera at the code. The page then counts your chats as they arrive.

personal is a name you choose. Each name is a separate WhatsApp account, so one server can hold several.

3. Connect your AI assistant

Add this address as a custom connector in Claude or ChatGPT, or as a remote MCP server in any other client:

https://whatsapp-mcp.<your-name>.workers.dev/accounts/personal/mcp

The app opens your server in the browser. Sign in with your SECRET and select Allow. In Claude Code that is:

claude mcp add --transport http whatsapp https://whatsapp-mcp.<your-name>.workers.dev/accounts/personal/mcp

In pi, add it and sign in from the terminal:

pi mcp add whatsapp --url https://whatsapp-mcp.<your-name>.workers.dev/accounts/personal/mcp
pi mcp login whatsapp

Scripts and clients that can set a header can skip the browser and send Authorization: Bearer <SECRET> instead.

What your assistant can do

Tools that send or change something tell your assistant so, and most assistants ask you before using them.

How it works

flowchart LR
  agent["AI assistant"] -- "MCP + OAuth" --> worker["Worker"]
  worker -- "RPC" --> account
  subgraph account["Durable Object, one per WhatsApp account"]
    socket["WhatsApp session<br/>whatsapp-rust in WASM"]
    archive[("SQLite archive<br/>full-text search")]
    socket --> archive
  end
  socket <-- "WebSocket" --> whatsapp["WhatsApp"]

Each WhatsApp account lives in its own Durable Object, a small server that Cloudflare keeps running with its own SQLite database. The WhatsApp session inside it is baileyrs, whose protocol core is whatsapp-rust compiled to WebAssembly. An alarm every 30 seconds keeps the object in memory and reconnects it after deploys.

WhatsApp sends your recent history once, when you link, and the archive keeps every message after that. Search finds people by any name they have used, and treats a person's phone number and their anonymous WhatsApp ID (LID) as the same person.

Configuration

With oauth, an app connects after you sign in with SECRET in the browser and allow it. With api_key, clients send Authorization: Bearer <SECRET> on every request. The pairing page asks for SECRET in every mode, and allows five attempts per minute.

Change the variables in wrangler.jsonc, or pass --var TIMEZONE:<zone> to wrangler deploy. OAuth grants live in a KV namespace that the first deploy creates. The pairing page also uses a small REST API under /accounts/:id: status, start, send and logout.

Costs

One personal account running 24/7 costs $5 per month, the price of Workers Paid. Its included usage covers everything one account does:

The object stays in memory all day, and Cloudflare bills that time as if it used the full 128 MB, however busy the account is. It also wakes every 30 seconds, which explains the 90,000 requests and rows. Linking saves the whole history at once: an account with about 30,000 messages wrote 258,000 rows in its first hour. Going past the included usage would take about 30,000 assistant calls or 100,000 new messages a day.

More accounts share the same plan. Cloudflare bills extra time in blocks of 1 million GB-s at $12.50, so two to four accounts cost $17.50 per month.

Workers Free is not enough, even for one account.

[!WARNING] Workers Free allows 100,000 written rows per day, fewer than the first sync writes. When an account crosses that limit, Cloudflare blocks every write until 00:00 UTC, so the server can't save new messages or schedule its heartbeat. Upgrading to Workers Paid lifts the block.

See Workers pricing, Durable Objects pricing and limits for current numbers.

Is it safe?

Your session and your messages stay in your Cloudflare account. The server talks only to WhatsApp, and only someone who knows your SECRET can use it or allow an app in.

This is an unofficial WhatsApp client, not affiliated with WhatsApp or Meta, and WhatsApp can ban accounts that use one. Link a number you can afford to lose, and keep your assistant asking before it sends messages.

Development

You need Bun. Wrangler comes with the project.

bun install
printf 'SECRET=%s\n' "$(openssl rand -hex 32)" > .dev.vars   # see .dev.vars.example
bun run dev     # http://localhost:8787/accounts/dev
bun run check   # types, lint, format and tests

To deploy from your machine, run bunx wrangler secret put SECRET once and then bun run deploy.

Built on baileyrs and whatsapp-rust. Message rendering and identity rules follow mautrix-whatsapp. Licensed under GPL-3.0.