online smtp test

smtp host

port

username (optional)

password (optional)

from email

to email

subject

message body

Use TLS/SSL

about online smtp test

Test your SMTP server configuration by sending a real test email and viewing the full SMTP conversation log — ideal for verifying mail server setups and troubleshooting delivery issues.

Setting up email delivery is one of the trickiest parts of building applications. This tool connects directly to your SMTP server and performs a complete mail transaction, showing you every step of the handshake: greeting, EHLO, authentication, MAIL FROM, RCPT TO, DATA, and the server's responses at each stage.

You can test any SMTP server by providing the hostname, port, and optionally your login credentials. The tool supports both plaintext and TLS-encrypted connections. Common configurations include Gmail (smtp.gmail.com:587 with TLS), Outlook (smtp-mail.outlook.com:587), and custom mail servers.

The full SMTP conversation log is displayed in a terminal-style view, making it easy to identify exactly where in the process things succeed or fail. This is invaluable for diagnosing authentication errors, relay restrictions, DNS issues, and firewall blocks.

The SMTP test is performed server-side. Your credentials are used only for the duration of the test and are never stored. For security, we recommend using app-specific passwords when testing services like Gmail that support them.