Lettr MCP
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MCP for Lettr transactional email API
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- Author
- lettr-com
- Categories
- Developer Tools, Automation, API, Communication
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Setup
Install Lettr MCP in your MCP client (Claude Desktop, Cursor, Windsurf, and others).
Repository: https://github.com/lettr-com/lettr-mcp
Follow the installation instructions in the repository README, then restart your MCP client.
- 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
- Send Emails— Send transactional emails with HTML, plain text, CC/BCC, attachments, tracking options, metadata, and tags. Supportstemplate-based sendingwith merge tag substitution, scheduled delivery, and inspecting sent messages and events.
- Templates— List, create, get, update, and delete email templates. Retrieve rendered HTML andmerge tagsto discover which variables a template expects before sending.
- Domains— List, create, get, delete, andverify sending domains. View DNS records required for SPF, DKIM, and DMARC authentication.
- Webhooks— List, create, get, update, and deletewebhook configurationsfor real-time email event notifications.
- Projects— List the projects available to your team so you can target template and email tools at a specific project.
- Audience— Manage contacts, lists, subscription topics, custom properties, and segments. Create and update contacts (with double opt-in), attach contacts to lists and topics, bulk import, and build segments from match conditions.
- System— Health check and API key validation for client setup and diagnostics.
- Create a freeLettr account
- Create an API keyin your dashboard
- Verify your domainto send emails to any recipient
claude mcp add lettr -e LETTR_API_KEY=lttr_xxxxxxxxx -- npx -y lettr-mcp
Open the command palette and choose "Cursor Settings" > "MCP" > "Add new global MCP server".
{ "mcpServers": { "lettr": { "command": "npx", "args": ["-y", "lettr-mcp"], "env": { "LETTR_API_KEY": "lttr_xxxxxxxxx" } } } }
Open Claude Desktop settings > "Developer" tab > "Edit Config".
{ "mcpServers": { "lettr": { "command": "npx", "args": ["-y", "lettr-mcp"], "env": { "LETTR_API_KEY": "lttr_xxxxxxxxx" } } } }
You can pass additional arguments to configure the server:
- --key: Your Lettr API key (alternative toLETTR_API_KEYenv var)
- --sender: Default sender email address from averified domain
- --reply-to: Default reply-to email address
- LETTR_API_KEY: Your Lettr API key (required)
- SENDER_EMAIL_ADDRESS: Default sender email address from a verified domain (optional)
- REPLY_TO_EMAIL_ADDRESS: Default reply-to email address (optional)
Note:If you don't provide a sender email address, the MCP server will ask for one each time you send an email.
git clone https://github.com/nicholasgriffintn/lettr-mcp.git cd lettr-mcp pnpm install pnpm run build
{ "mcpServers": { "lettr": { "command": "node", "args": ["ABSOLUTE_PATH_TO_PROJECT/dist/index.js"], "env": { "LETTR_API_KEY": "lttr_xxxxxxxxx" } } } }
Make sure you've built the project first (seeLocal Developmentabove).
- Choosestdio(launch a process).
- Command:node
- Args:dist/index.js
- Env:LETTR_API_KEY=lttr_your_key_here
- ClickConnect, then use "List tools" to verify the server is working.
- Lettr Website
- API Documentation
- MCP Setup Guide
- MCP Tools Reference
- Template Language
- DNS Setup Guides
- Knowledge Base
This is a web browser that enables your coding agent, such as Claude Code, to visit websites on your behalf and assist you in identifying bugs or creating UI test cases.
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Self-hosted email and SMS platform for AI agents — each agent gets a real email address, phone number, inbox, and API key.
Give your AI agent its own email address — instant bot inboxes via API, no human setup required.
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