Resend MCP Server

A comprehensive Model Context Protocol (MCP) server for the Resend email API. Enables AI assistants like Claude to send emails, manage domains, contacts, audiences, and more through a standardized interface.

Quick Run

Run immediately without installation:

# Using npx (Node.js)
npx mcp-resend

# Using Nix flakes (with binary cache from FlakeHub)
nix run "https://flakehub.com/f/gui-wf/resend-mcp-server/*"

# Using Nix flakes (from GitHub)
nix run github:gui-wf/resend-mcp-server

Requires RESEND_API_KEY environment variable. Get yours from Resend Dashboard.

Disclaimer

This is an unofficial, community-developed project. It is not affiliated with, endorsed by, or supported by Resend. Use at your own risk.

Claude Desktop Configuration

Add the following to your Claude Desktop configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

Using npx (Recommended)

{
  "mcpServers": {
    "resend": {
      "command": "npx",
      "args": ["mcp-resend"],
      "env": {
        "RESEND_API_KEY": "re_your_api_key_here"
      }
    }
  }
}

Using Nix

{
  "mcpServers": {
    "resend": {
      "command": "nix",
      "args": ["run", "github:gui-wf/resend-mcp-server", "--refresh"],
      "env": {
        "RESEND_API_KEY": "re_your_api_key_here"
      }
    }
  }
}

Installation

npm (Global)

npm install -g mcp-resend

From Source

git clone https://github.com/gui-wf/resend-mcp-server.git
cd resend-mcp-server
npm install
npm run build

Then configure Claude Desktop with:

{
  "mcpServers": {
    "resend": {
      "command": "node",
      "args": ["/path/to/resend-mcp-server/dist/index.js"],
      "env": {
        "RESEND_API_KEY": "re_your_api_key_here"
      }
    }
  }
}

Available Tools

Core Tools (Always Available)

| Tool | Description | |------|-------------| | send_email | Send a single email via Resend API | | get_email | Retrieve email details by ID | | list_domains | List all verified domains for the account | | search_resend_documentation | Search Resend API documentation with semantic search |

Secondary Tools

| Tool | Description | |------|-------------| | batch_send_email | Send multiple emails in a single request | | create_domain | Register a new email domain | | verify_domain | Initiate domain verification process | | list_emails | List sent emails with pagination | | get_domain | Get details for a specific domain |

Tertiary Tools (Advanced/Admin)

| Tool | Description | |------|-------------| | delete_domain | Delete a domain from the account | | update_domain | Update domain settings | | list_contacts | List contacts in an audience | | create_contact | Create a new contact | | get_contact | Get contact details | | update_contact | Update contact information | | delete_contact | Delete a contact | | list_audiences | List all audiences | | create_audience | Create a new audience | | get_audience | Get audience details | | delete_audience | Delete an audience | | list_api_keys | List API keys (names only) | | create_api_key | Create a new API key | | delete_api_key | Delete an API key |

Configuration

Environment Variables

| Variable | Required | Default | Description | |----------|----------|---------|-------------| | RESEND_API_KEY | Yes | - | Your Resend API key (must start with re_) | | RESEND_MCP_DEFAULT_TIER | No | core | Default tool tier: core, secondary, tertiary, or all | | RESEND_MCP_SCOPES | No | All | Comma-separated scopes: read, write, admin | | RESEND_RATE_LIMIT_MS | No | 500 | Minimum milliseconds between API requests | | RESEND_DEBUG | No | false | Enable debug logging (true, 1, or yes) |

Tool Tiers

Tools are organized into tiers for token efficiency:

• Core: Essential tools for basic email operations (4 tools)
• Secondary: Common additional features (5 tools)
• Tertiary: Advanced and administrative features (14 tools)

Configure the default tier based on your use case:

{
  "env": {
    "RESEND_API_KEY": "re_...",
    "RESEND_MCP_DEFAULT_TIER": "secondary"
  }
}

Scope-Based Access Control

Restrict tool access by operation type:

• read: Tools that only retrieve data
• write: Tools that create or modify resources
• admin: Tools for administrative operations

{
  "env": {
    "RESEND_API_KEY": "re_...",
    "RESEND_MCP_SCOPES": "read,write"
  }
}

Development

Prerequisites

• Node.js >= 20.0.0
• npm or pnpm
• (Optional) Nix for reproducible environment

Setup with Nix

# Enter development shell (auto-installs dependencies)
nix develop

Setup without Nix

npm install

Development Commands

| Command | Description | |---------|-------------| | npm run dev | Run server with hot reload | | npm run build | Compile TypeScript to dist/ | | npm run inspector | Debug with MCP Inspector | | npm test | Run test suite | | npm run test:run | Run tests once (CI mode) | | npm run typecheck | Validate TypeScript types | | npm run lint | Run ESLint | | npm run build:embeddings | Rebuild documentation embeddings |

Testing with MCP Inspector

The MCP Inspector provides an interactive UI for testing tools:

npm run inspector

This opens a web interface where you can:

• View all available tools
• Test tool execution with custom inputs
• Inspect request/response payloads

Architecture

See docs/ARCHITECTURE.md for detailed documentation on:

• Project structure
• Component interactions
• Data flow
• Customization points

Troubleshooting

See docs/TROUBLESHOOTING.md for solutions to common issues.

License

This project is licensed under the Apache License 2.0.

See the LICENSE file for details.

Links

• Resend API Documentation
• Model Context Protocol Specification
• MCP TypeScript SDK
• Changelog