MailboxValidator

Name: MailboxValidator
Author: MailboxValidator

by MailboxValidatorversion 1.0.0i★ –iRuns on your computer

Registry nameio.github.MailboxValidator/mcp-mailboxvalidator

Install

Overview

Description from the maker (original English)

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

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Chat & email
You need to fill in: MAILBOXVALIDATOR_API_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: MAILBOXVALIDATOR_API_KEY

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

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

Run this in your terminal

claude mcp add mailboxvalidator --env MAILBOXVALIDATOR_API_KEY=your-value -- npx -y mcp-mailboxvalidator

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

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

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "mailboxvalidator": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "mcp-mailboxvalidator"
      ],
      "env": {
        "MAILBOXVALIDATOR_API_KEY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

MAILBOXVALIDATOR_API_KEY secret required env
Your MailboxValidator API key.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account MailboxValidator, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Chat & emaili

More stars than 0% of the other 1765 servers in this category
Published to the registry more recently than 10% of the other 1765 servers in this category
Basic checks equal to or better than 100% of the other 1765 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is MailboxValidator safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: MAILBOXVALIDATOR_API_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (1.0.0) reached the registry 5 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Vexa, emailmd, MCP WhatsApp Cloud

Alternatives

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Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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by Vexa-ai

Meeting bot and transcripts for Google Meet, Teams and Zoom. Live or after, speakers labelled.

Runs in the cloud★ 2,949Apache-2.0Updated 2 months ago

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emailmd

by anypost

Render markdown into email-safe HTML, lint drafts for deliverability problems, and preview emails.

Computer or cloud★ 1,385MITUpdated 31 days ago

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MCP WhatsApp Cloud

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Runs on your computer★ 277MITUpdated 5 months ago

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

MailboxValidator MCP server

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

Features

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.

Requirement

This MCP server requires an API key. You can also sign up for a free API key and enjoy up to 300 queries per month.

The local MCP server setup also uses Node.js and npm, which can be downloaded at Node.js website.

Setup

There are two ways to use this MCP server:

Cloud-hosted MCP server: Connect directly to the hosted MailboxValidator MCP server. Nothing needs to be installed locally.
Local MCP server: Download and run the server on your own machine.

Option 1: Cloud-hosted MCP server

Use this if you want to connect directly to the hosted server.

Method A: Direct HTTP connection

Use this if your MCP client supports remote servers over HTTP. No Node.js, npm, or npx is needed.

"mcpServers": { "mailboxvalidator": { "type": "http", "url": "https://mcp.mailboxvalidator.com/mcp", "headers": { "X-API-Key": " " } } } }

If your client is configured from the command line, such as Claude Code, you can add the server with:

claude mcp add --transport http mailboxvalidator https://mcp.mailboxvalidator.com/mcp --header "X-API-Key: <YOUR_API_KEY>"

Method B: Connection through `npx`

Use this if your MCP client only supports local (stdio) servers. The mcp-remote package runs locally and forwards requests to the hosted server. Node.js is required.

"mcpServers": { "mailboxvalidator": { "command": "npx", "args": [ "-y", "mcp-remote@latest", "https://mcp.mailboxvalidator.com/mcp", "--header", "X-API-Key: " ] } } }

To get your API key, just login to your dashboard and get it from there, then replace in the example above with your actual API key.

Restart the Claude Desktop after saving the changes, and you should see it appear in the Search and tools menu.

Option 2: Local MCP server

Follow the steps to run the MCP server on your own machine:

Download the repository to your local.
Run the following commands while inside the project folder to install dependencies and build the server.

npm install

npm run build

3. Make sure you have installed Claude Desktop. If you haven't, kindly download from [here](https://claude.ai/download) for Windows and macOS users, or follow [this guide](https://modelcontextprotocol.io/quickstart/client) for Linux users.

Open claude_desktop_config.json. If you don't have that file yet, follow this guide to create one.
Add the following to your claude_desktop_config.json:

"mcpServers": { "mailboxvalidator": { "command": "node", "args": [ "C:\\path\\to\\mcp-mailboxvalidator\\build\\index.js" ], "env": { "MAILBOXVALIDATOR_API_KEY": " " } } } }

 6. Remember to replace the path for the `index.js` with your actual path to your MailboxValidator MCP server on your local machine.

To get your API key, just login to your dashboard and get it from there. Replace the in the above with your actual API key.
Restart the Claude Desktop after saving the changes, and you should see it appear in the Search and tools menu.

Usage

Just enter your query about the email address in a chat in Claude Desktop. Some of example queries are:

Is (email) a valid email address?
Is (email) a fake email?
Is (email) a free email?

In Claude Desktop, the model will automatically generate the output based on the result returned by MailboxValidator MCP server.

Environment Variable

MAILBOXVALIDATOR_API_KEY

The free MailboxValidator API key allows you to query up to 300 emails per month. If you require more, you can sign up for a paid API plan.

Tool

validate_email

Description Validates the email address given. It helps users to determine if an email address is potentially reachable by checking the syntax, DNS, MX server, disposable list and more.

Arguments email (str): The email address to validate.

Returns A JSON string containing the validation data. The result includes the following fields:

Syntax: Checks that the email address conforms to how an email address should look like.
DNS & MX Server: Checks that the domain DNS has an MX server specified.
Network & Connectivity: Attempts connection to the MX server to make sure it's operational.
Greylisting: Checks if MX server is using greylisting that could cause email sent to that address to bounce.
Disposable List: Checks if the email domain is from a temporary or disposable email provider.
High Risk & Suppressed List: Checks if email username looks high-risk or if the email address is found in a suppression list.
Others: Checks the reputation score for the email and more..

If the request fails, the tool will return an error message as a string.

check_disposable_email

Description Checks if the email address given is from a disposable email provider.

Arguments email (str): The email address to check.

Returns A JSON string containing the disposable email data. The result includes the following fields:

Disposable List: Checks if the email domain is from a temporary or disposable email provider.

If the request fails, the tool will return an error message as a string.

check_free_email

Description Checks if the email address given is from a free email provider.

Arguments email (str): The email address to check.

Returns A JSON string containing the free email data. The result includes the following fields:

Free Email List: Checks if the email domain is from a free email provider.

If the request fails, the tool will return an error message as a string.

License

See the LICENSE file.

MailboxValidator

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Chat & emaili

Common questions

Alternatives

Vexa

emailmd

MCP WhatsApp Cloud

README from the maker

MailboxValidator MCP server

Features

Requirement

Setup

Option 1: Cloud-hosted MCP server

Method A: Direct HTTP connection

Method B: Connection through npx

Option 2: Local MCP server

Usage

Environment Variable

Tool

License

Method B: Connection through `npx`