How do I install Mailsend?

Mailsend is a local plugin. Install it using npm package: @reneturcios/mailsend and add the generated configuration snippet to your AI app's MCP config file. Then restart your AI app.

Is Mailsend safe to use?

Mailsend was flagged by MCP Marketplace's security scan, scoring 4.8/10 (high risk). It has 2 high or critical findings to review. Review the security report on this page carefully before installing it.

What credentials does Mailsend need?

Mailsend requires the following credentials or environment variables: RESEND_API_KEY. You can find setup instructions on the server detail page.

What AI apps work with Mailsend?

Mailsend uses the Model Context Protocol (MCP) and works with any MCP-compatible AI app, including Claude, ChatGPT / Codex, Gemini, Copilot, Cursor, and more.

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Mailsend MCP Server

by CloudCorpRecords

Developer ToolsUse Caution4.8MCP RegistryLocal

Free

Server data from the Official MCP Registry

Send and manage email, domains, audiences, and API keys through the Resend API.

About

Send and manage email, domains, audiences, and API keys through the Resend API.

Security Report

4.8

Use Caution4.8High Risk

mailsend is a transparent wrapper around the documented Resend REST API. It requires RESEND_API_KEY, sends it only as a Bearer token to api.resend.com, and has no hardcoded secrets, shell execution, or exfiltration paths. The main concern is that the agent can create, list, and delete API keys (including full_access keys), which is a high-privilege capability that users should consciously accept. Supply chain analysis found 4 known vulnerabilities in dependencies (0 critical, 2 high severity). Package verification found 1 issue.

8 files analyzed · 8 issues found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

HTTP Network Access

Connects to external APIs or services over the internet.

env_vars

Check that this permission is expected for this type of plugin.

What You'll Need

Set these up before or after installing:

RESEND_API_KEYRequired

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "io-github-cloudcorprecords-mailsend": {
      "env": {
        "RESEND_API_KEY": "your-resend-api-key-here"
      },
      "args": [
        "-y",
        "@reneturcios/mailsend"
      ],
      "command": "npx"
    }
  }
}

Documentation

View on GitHub

From the project's GitHub README.

mailsend

mailsend lets an agent run the sending side of a Resend account: send a message and look it back up, set up a sending domain and start its DNS verification, mint or retire API keys, and keep audiences and their contacts in order. Each operation is one call against the Resend REST API, and the API's JSON answer comes back as-is. It runs from the command line or as an MCP server for agents.

A Resend API key is required. Put it in the RESEND_API_KEY environment variable; the key is sent to the API as a Bearer token and never appears in output. When the variable is missing, every operation fails with an error that names it.

Install

npx @reneturcios/mailsend list-domains

Or run the container image:

docker run -i -e RESEND_API_KEY ghcr.io/cloudcorprecords/mailsend

The container defaults to the MCP server (see below). Pass CLI arguments to use it as a CLI instead.

CLI

export RESEND_API_KEY="your API key"

mailsend send --from "Acme <hello@acme.example>" --to user@example.com \
  --subject "Welcome" --text "Hello there"
mailsend list-emails --limit 10
mailsend list-domains
mailsend list-audiences

mailsend --version

Exit codes: 0 on success, 1 when an API call fails (including a missing RESEND_API_KEY), 2 for usage errors.

MCP server

One bin serves both faces. The mcp subcommand starts a stdio MCP server:

npx -y @reneturcios/mailsend mcp

MCP client configuration:

{
  "mcpServers": {
    "mailsend": {
      "command": "npx",
      "args": ["-y", "@reneturcios/mailsend", "mcp"],
      "env": { "RESEND_API_KEY": "your API key" }
    }
  }
}

Tools

Tool	Input	What it does
`send_email`	`from`, `to` (array), `subject` (required); `html`, `text`, `cc`, `bcc`, `reply_to` (optional)	Send an email.
`list_emails`	`limit` (integer, optional)	List sent emails.
`get_email`	`id` (required)	Get one sent email by ID.
`create_domain`	`name` (required), `region` (optional)	Create a sending domain.
`list_domains`	—	List sending domains.
`get_domain`	`id` (required)	Get one domain, including its DNS records.
`verify_domain`	`id` (required)	Start DNS verification for a domain.
`delete_domain`	`id` (required)	Delete a sending domain.
`create_api_key`	`name` (required), `permission`, `domain_id` (optional)	Create an API key.
`list_api_keys`	—	List API keys.
`delete_api_key`	`id` (required)	Delete an API key.
`create_audience`	`name` (required)	Create an audience.
`list_audiences`	—	List audiences.
`create_contact`	`audience_id`, `email` (required); `first_name`, `last_name`, `unsubscribed` (optional)	Add a contact to an audience.
`list_contacts`	`audience_id` (required), `limit` (optional)	List contacts in an audience.

This is a documented core subset of the Resend platform surface. The hosted Resend MCP also covers broadcasts, templates, webhooks, segments, topics, contact properties, batch sending, and received (inbound) email; those groups are not implemented here.

Development

npm install
npm run build   # tsc -> dist/
npm test        # node test runner over test/*.test.ts, no network (fake fetch fixtures)
npm run dev     # run the CLI from source via tsx

License

MIT — see LICENSE.

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