Last week I shipped an MCP server that validates email addresses. No third-party APIs. No per-request fees. Just DNS lookups.

It's called Email Verify MCP and it's my 62nd open-source tool on Smithery.

How most email verification works (expensive)

Services like ZeroBounce, NeverBounce, and Hunter charge $0.008–$0.01 per verification. If you're onboarding 100,000 users, that's $800–$1,000 just to check emails. These services resell DNS lookups with a markup.

What I built instead

Email Verify MCP does the same thing using raw DNS queries:

MX record check — does the domain accept mail?

SMTP handshake — can the mailbox actually receive?

Disposable domain detection — flags temp emails from services like Mailinator

Role account detection — catches admin@ , noreply@ , support@

Zero API costs.…