Focused tool

SMTP transport analyzer

Inspect public MX transport, banner, EHLO, and STARTTLS without sending mail.

Run SMTP transport analyzer

Usage and limits

Public network lookups use the canonical v1 JSON API with the existing input validation, timeout, response-size, rate, and SSRF controls. Local transformations remain in this browser.

API documentation: API reference. Canonical route: /api/v1/smtp-test/.