What is the Mailjet MCP server

The Mailjet MCP the AI assistant Claude Desktop read Mailjet data from your account using your API key. Once it is set up, you can ask Claude for campaign performance, contact lists or statistics and it will fetch the information through the Mailjet API.

MCP (Model Context Protocol) is a way for AI tools to connect to external services. The Mailjet MCP server is a small service that runs on your computer and exposes Mailjet APIs to Claude. This allows Claude to answer questions using live data from your Mailjet account.

What you need before you start

This setup asks a non technical user to do a few technical things. To make it easier, we will show the tools you need and how to install them.

• Mailjet account with an active API key and secret key
• Claude Desktop installed 
• Git to download the Mailjet MCP server from GitHub
• Node.js to run the MCP server
• pnpm to install the MCP server files
• Permission to edit Claude Desktop configuration

Step 1. Download the project

You will download the Mailjet MCP server from the official GitHub repository and move into that folder.

1. Open Terminal (Mac) or Command Prompt (Windows).

2. Run:

   git clone https://github.com/mailgun/mailjet-mcp-server.git
   cd mailjet-mcp-server
   

The first command downloads the MCP server into a new folder. The second command moves you into that folder so the next commands work.

Step 2. Install the dependencies

Next, install the packages the server needs.

pnpm install

Step 3. Start (turn on) the MCP server

This step starts the Mailjet MCP program so that Claude can connect to it.

1. Make sure you are still inside the mailjet-mcp-server folder.

2. Run:

   node src/mailjet-mcp.js
   

This launches the Mailjet MCP server on your computer. You may see a few lines of text. That means it is running.

Step 4. Connect Claude Desktop

Claude Desktop uses a JSON configuration file to know which MCP servers to load. Add the Mailjet MCP server there so Claude can find it.

~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "mailjet": {
      "command": "node",
      "args": ["/YOUR/PATH/mailjet-mcp-server/src/mailjet-mcp.js"],
      "env": {
        "MAILJET_API_KEY": "YOUR_public_key:YOUR_private_key"
      }
    }
  }
}

%APPDATA%/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "mailjet": {
      "command": "node",
      "args": ["C:\\PATH\\TO\\mailjet-mcp-server\\src\\mailjet-mcp.js"],
      "env": {
        "MAILJET_API_KEY": "YOUR_public_key:YOUR_private_key"
      }
    }
  }
}

Environment variables

The Mailjet MCP server supports the following environment variables.

You can define these in your system or directly in the Claude configuration in the env section.

Testing the setup

The project includes a local test suite. To run it:

NODE_ENV=test pnpm test

If the tests pass without errors, your installation is working.

Troubleshooting

• Claude does not show Mailjet tools
  Check that the path in claude_desktop_config.json points to your real mailjet-mcp-server/src/mailjet-mcp.js file. Restart Claude.
• Authentication error
  Make sure the API value uses the format PUBLIC_KEY:PRIVATE_KEY. If the colon is missing, authentication fails.
• Server closes immediately
  Run node src/mailjet-mcp.js from inside the mailjet-mcp-server folder.
• EU account not loading
  Set MAILJET_API_REGION=eu in your environment or in the env section of the Claude config entry.

Using Mailjet MCP in Claude Desktop

Once the MCP server is running and Claude Desktop has restarted, you can start using it.

1. Open Claude Desktop.
2. Ask a Mailjet related question, for example: Which of my contact lists has the most subscribers.
3. Claude will detect that it needs to contact Mailjet and will show a box similar to: Claude wants to use Get v3 liststatistics from mailjet.

4. You will see buttons such as Deny, Allow once, and Always allow.

   • Allow once lets Claude make this single request to Mailjet now.
   • Always allow tells Claude it can use the Mailjet MCP server for future requests without asking again.
   • Deny blocks the request and Claude will not get Mailjet data.

   

   1. Choose Allow once if you just want to test the configuration
   2. Choose Always allow if you want to allow Claude to run the request each time without having to re-request permission.

5. After you allow the request, Claude will call the Mailjet MCP server, get the data and respond with the result, for example a list of your contact lists and their subscriber counts.