Lettr MCP Server

MCP server for the Lettr email API — send transactional emails, manage templates, domains, and webhooks from any AI assistant

Local serverstdioPython

What is the Lettr MCP MCP server?

Lettr MCP MCP server is a locally run integration for AI assistants that speak the Model Context Protocol. MCP server for the Lettr email API — send transactional emails, manage templates, domains, and webhooks from any AI assistant.

What you get

Lettr is a modern email sending platform built for developers. It offers a clean REST API, a powerful drag-and-drop template editor, merge tag personalization, open and click tracking, and best-in-class deliverability. Whether you're sending password resets, order confirmations, or onboarding sequences, Lettr makes it simple and reliable.

  • API Reference — — Full REST API documentation
  • Templates — — Visual email editor with merge tags
  • Domains — — Domain verification and DNS setup
  • Webhooks — — Real-time event notifications
  • Quickstart Guides — — Node.js, PHP, Laravel, Python, Go, Rust, and more

Setting it up

Installation goes through your MCP client rather than a global install: point it at lettr-mcp on npm and it is fetched when the client starts. The copy-paste blocks for Claude Desktop, Claude Code and Cursor are further down this page.

What the assistant can call

Once Lettr MCP is connected, these are the calls the assistant has available:

  • Cursor — Open the command palette and choose "Cursor Settings" > "MCP" > "Add new global MCP server"
  • Options — The Options tool exposed by this server
  • Emails — The Emails tool exposed by this server
  • Templates — The Templates tool exposed by this server
  • Domains — The Domains tool exposed by this server
  • Webhooks — The Webhooks tool exposed by this server
  • Projects — The Projects tool exposed by this server
  • Audience — The Audience tool exposed by this server
  • System — The System tool exposed by this server

Configuration and credentials

You will need one environment variable: LETTR_API_KEY. The server will not start without them, which is usually why the tools fail to appear on a first run. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

Before you rely on it

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • With 9 tools registered it takes up a noticeable share of the context window; turn it off in projects that never touch Lettr MCP.
  • Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the lettr mcp mcp server does with a few real requests.

Choosing this one

This sits in the team communication group, where several servers overlap in what they claim to do but differ sharply once you actually set them up. Lettr MCP's toolset — Cursor, Options, Emails and 6 more — is a fair guide to whether it matches your workflow. It is maintained by lettr-com; worth a glance at recent repository activity before you build anything load-bearing on it.

This entry was verified against Lettr MCP's own documentation before publication; SyncDev keeps the directory reviewed rather than auto-generated.

Available tools

ToolWhat it does
CursorOpen the command palette and choose "Cursor Settings" > "MCP" > "Add new global MCP server".
OptionsThe Options tool exposed by this server.
EmailsThe Emails tool exposed by this server.
TemplatesThe Templates tool exposed by this server.
DomainsThe Domains tool exposed by this server.
WebhooksThe Webhooks tool exposed by this server.
ProjectsThe Projects tool exposed by this server.
AudienceThe Audience tool exposed by this server.
SystemThe System tool exposed by this server.

How to install the Lettr MCP MCP server

{
  "mcpServers": {
    "lettr": {
      "command": "npx",
      "args": ["-y", "lettr-mcp"],
      "env": {
        "LETTR_API_KEY": "your-value"
      }
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

VariableDescriptionRequired
LETTR_API_KEYCredential the server authenticates with.Yes

Example prompts to try

  • Use Lettr MCP to Cursor.
  • Use Lettr MCP to Options.
  • Use Lettr MCP to Emails.

Frequently asked questions

It connects Lettr MCP to MCP-compatible AI assistants such as Claude and Cursor, exposing 9 tools (Cursor, Options, Emails, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Lettr MCP directly.