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What is an MCP Server?

MCP is an open protocol that standardizes how applications provide context to LLMs. Among other benefits, it provides LLMs tools to act on your behalf.

What can Resend’s MCP Server do?

Resend’s MCP Server gives your AI agent native access to the full Resend platform through a single integration. You can manage all aspects of your email infrastructure using natural language.
  • Emails — Send, list, get, cancel, update, and batch send emails. Supports HTML, plain text, attachments (local file, URL, or base64), CC/BCC, reply-to, scheduling, tags, and topic-based sending.
  • Received Emails — List and read inbound emails. List and download received email attachments.
  • Contacts — Create, list, get, update, and remove contacts. Manage segment memberships and topic subscriptions. Supports custom contact properties.
  • Broadcasts — Create, send, list, get, update, and remove broadcast campaigns. Supports scheduling, personalization placeholders, and preview text.
  • Domains — Create, list, get, update, remove, and verify sender domains. Configure tracking, TLS, and sending/receiving capabilities.
  • Segments — Create, list, get, and remove audience segments.
  • Topics — Create, list, get, update, and remove subscription topics.
  • Contact Properties — Create, list, get, update, and remove custom contact attributes.
  • API Keys — Create, list, and remove API keys.
  • Webhooks — Create, list, get, update, and remove webhooks for event notifications.
As an example, you could use this to automate email workflows, manage your contact database, or build AI-powered email campaigns.

Prerequisites

The Resend MCP server is available on NPM and can be easily integrated into any supported MCP client using npx. To use the MCP Server, you’ll need to:

How to use the MCP Server

The server supports two transport modes: stdio (default) and HTTP. Choose your preferred mode and client below to get started. Remember to replace re_xxxxxxxxx with your actual API key.

Stdio Transport (Default)

claude mcp add --env RESEND_API_KEY=re_xxxxxxxxx resend -- npx -y resend-mcp

HTTP Transport

Run the server over HTTP for remote or web-based integrations. In HTTP mode, each client authenticates by passing their Resend API key as a Bearer token in the Authorization header. Start the server:
npx -y resend-mcp --http --port 3000
The server will listen on http://127.0.0.1:3000 and expose the MCP endpoint at /mcp using Streamable HTTP.
claude mcp add resend --transport http http://127.0.0.1:3000/mcp --header "Authorization: Bearer re_xxxxxxxxx"
You can also set the port via the MCP_PORT environment variable:
MCP_PORT=3000 npx -y resend-mcp --http

Options

You can pass additional arguments to configure the server:
  • --key: Your Resend API key (stdio mode only; HTTP mode uses the Bearer token from the client)
  • --sender: Default sender email address from a verified domain
  • --reply-to: Default reply-to email address (can be specified multiple times)
  • --http: Use HTTP transport instead of stdio (default: stdio)
  • --port: HTTP port when using --http (default: 3000, or MCP_PORT env var)
Environment variables:
  • RESEND_API_KEY: Your Resend API key (required for stdio, optional for HTTP since clients pass it via Bearer token)
  • SENDER_EMAIL_ADDRESS: Default sender email address from a verified domain (optional)
  • REPLY_TO_EMAIL_ADDRESSES: Comma-separated reply-to email addresses (optional)
  • MCP_PORT: HTTP port when using --http (optional)
If you don’t provide a sender email address, the MCP server will ask you to provide one each time you call the tool.

Local Development

Clone the project and build:
git clone https://github.com/resend/resend-mcp.git
pnpm install
pnpm run build
To use the local build, replace the npx command with the path to your local build:

Stdio

claude mcp add --env RESEND_API_KEY=re_xxxxxxxxx resend -- node ABSOLUTE_PATH_TO_PROJECT/dist/index.js

HTTP

First, start the local HTTP server:
node ABSOLUTE_PATH_TO_PROJECT/dist/index.js --http --port 3000
Then configure your client:
claude mcp add resend --transport http http://127.0.0.1:3000/mcp --header "Authorization: Bearer re_xxxxxxxxx"

Testing with MCP Inspector

Make sure you’ve built the project first (see Local Development section above).

Using Stdio Transport

1

Set your API key

export RESEND_API_KEY=re_your_key_here
2

Start the inspector

pnpm inspector
3

Configure in the browser

In the Inspector UI:
  • Choose stdio (launch a process)
  • Command: node
  • Args: dist/index.js (or the full path to dist/index.js)
  • Env: RESEND_API_KEY=re_your_key_here (or leave blank if you already exported it in the same terminal)
  • Click Connect, then use “List tools” to verify the server is working

Using HTTP Transport

1

Start the HTTP server

In one terminal:
node dist/index.js --http --port 3000
2

Start the inspector

In another terminal:
pnpm inspector
3

Configure in the browser

In the Inspector UI:
  • Choose Streamable HTTP (connect to URL)
  • URL: http://127.0.0.1:3000/mcp
  • Add a custom header: Authorization: Bearer re_your_key_here and activate the toggle
  • Click Connect, then use “List tools” to verify the server is working