MailboxValidator MCP Server

Email validation MCP server using the MailboxValidator API. It can validate email addresses.

Local serverstdio

What is the MailboxValidator MCP server?

Connect MailboxValidator to Claude, Cursor or any other MCP client and it stops being a tab you switch to. Email validation MCP server using the MailboxValidator API. It can validate email addresses. The mailboxvalidator mcp server is what makes that connection.

What the server does

This is a simple Model Context Protocol (MCP) server implementation for MailboxValidator API. It will return validation result for an email address.

  • Comprehensive Email Validation — Checking an email address to see if an email is reachable by checking the syntax, DNS, MX server, high risk, suppressed list, and more
  • Disposable Email — Checking an email address to see if it's from a temporary/disposable email provider
  • Free Email — Checking an email address to see if it's from a free email provider

Installation

Installation goes through your MCP client rather than a global install: point it at npm 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.

Credentials and setup notes

Configuration is passed through the environment: MAILBOXVALIDATOR_API_KEY, YOUR_API_KEY. Treat anything key-shaped as a real credential — scope it to the minimum the server needs, and rotate it if it ever lands in a shared config.

Where it fits

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. It is maintained by MailboxValidator; worth a glance at recent repository activity before you build anything load-bearing on it.

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

Worth knowing first

  • 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.
  • Missing credentials fail quietly in some clients — if no tools show up, check the environment block first.
  • Keep per-call confirmation enabled while you learn its behaviour; it is the cheapest safeguard you have.

How to install the MailboxValidator MCP server

{
  "mcpServers": {
    "mailboxvalidator": {
      "command": "npx",
      "args": ["-y", "npm"],
      "env": {
        "MAILBOXVALIDATOR_API_KEY": "your-value",
        "YOUR_API_KEY": "your-value"
      }
    }
  }
}

Add to claude_desktop_config.json, then restart Claude Desktop.

Configuration

VariableDescriptionRequired
MAILBOXVALIDATOR_API_KEYCredential the server authenticates with.Yes
YOUR_API_KEYCredential the server authenticates with.Yes

Frequently asked questions

It connects MailboxValidator to MCP-compatible AI assistants such as Claude and Cursor. Instead of copying data back and forth by hand, the assistant works with MailboxValidator directly.