MailTester Ninja MCP Server

by mailtester Your server? Claim it

answering

MailTester Ninja is answering right now. Last checked 2 min ago. It exposes 2 tools.

Verify email addresses live against their mail server and find work emails. Nothing stored.

Uptime history 6 days of history

6 days agonow

100.0%

Uptime 24h

92 of 92 checks

Tools

read from the server

256 ms

Response time

average over 24h

open, no key

Access

streamable-http

What changed 9

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 30 October 2026. No other catalogue keeps this.

1 Nov a tool changed version3 times that day

1 Nov a tool description was rewritten find_email

31 Oct a tool changed version2 times that day

31 Oct a tool description was rewritten find_email

31 Oct a tool changed the parameters it asks for find_email

30 Oct a tool changed version

and 3 more, back to 30 October 2026

Nothing serious here today

Today is the operative word: we check MailTester Ninja every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 2 min ago.

Claude Code Claude Desktop Codex Cursor VS Code

run in your terminal

claude mcp add email-verification --transport http https://mcp.mailtester.ninja/mcp

Settings → Connectors → Add custom connector, then paste this address

https://mcp.mailtester.ninja/mcp

~/.codex/config.toml

[mcp_servers.email-verification]
url = "https://mcp.mailtester.ninja/mcp"

.cursor/mcp.json

{
  "mcpServers": {
    "email-verification": {
      "url": "https://mcp.mailtester.ninja/mcp"
    }
  }
}

.vscode/mcp.json

{
  "servers": {
    "email-verification": {
      "type": "http",
      "url": "https://mcp.mailtester.ninja/mcp"
    }
  }
}

Available tools 2

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

find_email

Find the work email address of a business contact, for professional outreach, from their first name, last name and company domain. The company's common address formats (first.last, flast, first, firstlast, first_last, f.last) are checked one by one with the company's own mail server, and the first one it accepts is returned. No database is searched and nothing is stored. Stops early when the domain accepts every address (catch-all) and then gives the most common format as "guess". Each format checked counts as one verification. Personal email providers such as gmail.com are refused. Requires a paid MailTester Ninja key.

verify

verify_email

Check in real time whether an email address exists and can receive mail, by asking the recipient's mail server (no message is sent). Returns code "ok" (valid), "ko" (invalid) or "mb" (uncertain, such as a catch-all domain) with a message.

Endpoints

URL	Transport	State	Latency	Checked
https://mcp.mailtester.ninja/mcp	streamable-http	answering	293 ms	2 min ago

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MailTester Ninja — questions

Answers built from our own checks of this server.

What can MailTester Ninja do?

It exposes 2 tools, read directly from the server on our last check. Among them: find_email, verify_email. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →

Is MailTester Ninja working right now?

We send a real MCP handshake every 15 minutes. Over the last 24 hours 92 of 92 checks got a reply (100.0%), average response time 256 ms. The bar chart above shows every period we have measured.

How do I connect MailTester Ninja?

Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.

Does MailTester Ninja need an API key?

No. MailTester Ninja completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 2 of them are readable on this page. This is what we observed, not what the docs claim.

How fast is MailTester Ninja?

It answers our handshake in 256 ms on average, which is faster than 55% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.