SMTP Test Tool

Check that your mail server accepts connections, negotiates TLS, authenticates and delivers — with a full step-by-step log.

The test runs from our server over an encrypted connection. Your credentials are used once and never logged or stored.

About the SMTP test tool

This tool connects to your outgoing mail (SMTP) server exactly as an email client would. It checks whether the server is reachable on the chosen port, whether it negotiates encryption (STARTTLS on 587 or implicit SSL/TLS on 465), whether your username and password authenticate, and — if you fill in the from/to fields — whether it will accept a test message for delivery.

Use it to diagnose "connection refused", "authentication failed" and TLS errors when setting up transactional email or a contact form. For security, only standard SMTP ports (25, 465, 587, 2525) and public mail servers are allowed, and your password is never written to the log or stored anywhere.