MailStream

The missing MCP server for physical mail.

There are 12,000+ MCP servers in the AI agent ecosystem. Zero are for physical mail, except this one. MailStream’s MCP server gives any compatible AI agent the ability to send real postcards, letters, and verify addresses autonomously.

Install the MCP serverView REST API

Background

What is MCP?

The Model Context Protocol (MCP) is an open standard that lets AI agents discover and use external tools. When you install an MCP server, every compatible agent, Claude, GPT, LangChain agents, CrewAI crews, AutoGen workflows, can call its tools without custom integration code.

Think of MCP as the USB port for AI agents. Plug in the MailStream MCP server and your agent can send physical mail the same way it sends emails, queries databases, or calls APIs, natively, with no glue code.

12 tools

Everything an agent needs to manage physical mail.

From sending a single postcard to running a multi-thousand-piece campaign with address verification and analytics, the MCP server exposes it all as callable tools.

Compatibility

Works with every major AI agent framework.

MCP is an open protocol. Any agent or application that supports MCP tool discovery can use MailStream’s server with zero custom code.

Installation

Up and running in 60 seconds.

Install the MCP server via npm, configure your API key, and point your agent at it. The server registers all 12 tools automatically.

Install the MCP server

  1. 1. Install the server

    npm install -g @mailstream/mcp-server

  2. 2. Add to your MCP config

    {
  "mcpServers": {
    "mailstream": {
      "command": "mailstream-mcp",
      "env": {
        "MAILSTREAM_API_KEY": "ms_live_..."
      }
    }
  }
}

  3. 3. Ask your agent to send mail

    "Send a thank-you postcard to Jane Cooper at 456 Oak Ave, Austin TX 78701. Use the thank-you template and include offer code SAVE20."

  4. 4. Pixel perfect response every time

    The thank-you postcard for Jane Cooper has been successfully created and scheduled for mailing.

Postcard Details:
• Recipient: Jane Cooper, 456 Oak Ave, Austin, TX 78701
• Size: 4x6
• Status: Pending (Scheduled for 2026-04-16)
• Postcard UUID: psc_7KDJ3nAqLwP9xTzE4mB2
• Campaign UUID: cmp_2HfL9QwXcR8uYpV1ZkM6
• Preview: View PDF Preview (https://assets.mailstream.app/postcards/psc_7KDJ3nAq_preview.pdf)

The front features a clean "Thank You" design, and the back includes your personalized message with offer code SAVE20.

First-mover advantage

Why being first matters in MCP.

Agents don’t comparison shop. Once a tool is embedded in a workflow, switching costs are high, prompts, workflows, and tutorials all reinforce the same choice.

0
Other MCP servers for physical mail
12
Tools available to AI agents
$52.6B
Projected AI agent market by 2030
Native MCP integration
lets any compatible AI agent discover and use MailStream tools instantly, no custom integration required.
12 ready-to-use tools
give agents full control over physical mail from sending postcards to verifying addresses and tracking delivery.
No glue code required
means your agent can send real mail as easily as calling an API or querying a database.
Built for agent workflows
so prompts, automations, and templates all work seamlessly with physical mail from day one.