MailTester Ninja MCP: live email verification in your AI app

MailTester Ninja's official MCP server checks an email address live against its mail server and finds work emails, and MailTester Ninja says nothing is stored. ContextGate connects it to Claude, ChatGPT and Cursor; switch off email finding if your team should only verify addresses it already has, and every check shows up in Activity.

  • Ready to connect
  • Free

Add MailTester Ninja to Claude, ChatGPT or Cursor

  1. 1Click Connect MailTester Ninja free and sign in with your MailTester Ninja account.
  2. 2Once connected, you'll see the full tool list, everything on. Finding someone's work email is a different job from checking a list, so switch off the email finder if verification is all you want.
  3. 3Add ContextGate to your AI app as a connector or MCP server. The steps for each app are on the Works with page.
  4. 4Paste a few signup emails into your AI app and ask which ones are valid, then open Activity to see each verification.

Email checks from Claude or ChatGPT

  • Verify an address against its mail server before you send.
  • Clean a list of addresses before an outreach campaign.
  • Find work emails for people you're trying to reach.

Handling addresses responsibly

  • Switch off email finding and keep verification.
  • A policy can warn or block before a lookup that would find someone's work email.
  • Activity records every verification and lookup.

What you get with MailTester Ninja and ContextGate

  • Your AI apps can use MailTester NinjaClaude, Cursor, ChatGPT and other AI apps reach MailTester Ninja through the one ContextGate connection you add to them.
  • You choose which tools they can useSwitch off any MailTester Ninja tool you don't want used. It's hidden from your AI apps and refused if called.
  • Every call is checked and recordedYour policies check each call (for example, personal data is hidden and secrets are blocked), and Activity keeps a record of it.

ContextGate sees only the tool calls that go through it, not your AI app's built-in tools or your chats.

MailTester Ninja tools

MailTester Ninja's own MCP server shows its tools once you sign in. When you connect it, they are listed and synced in your workspace.