SMTP Tester

SMTP Tester

Test your SMTP server configuration by sending a test email

SMTP Configuration
Enter your SMTP server details and compose a test email
Quick Reference

Common SMTP Servers

smtp.gmail.com:587Gmail (TLS)

smtp.office365.com:587Office 365 (TLS)

smtp.sendgrid.net:587SendGrid (TLS)

Port Reference

  • 25 - Standard SMTP (STARTTLS)
  • 587 - Submission port (STARTTLS)
  • 2525 - Alternative STARTTLS
  • 2587 - Alternative STARTTLS
  • 465 - SSL/TLS encrypted

Tips

  • Use email or username for auth
  • Use app-specific passwords for Gmail
  • Check firewall settings if connection fails

Why Choose SMTP Tester?

Powerful tools for testing and validating your email infrastructure

Quick Validation

Test your SMTP configuration instantly without complex setup. Get immediate feedback on connection and authentication.

Detailed Reports

Receive comprehensive error messages and diagnostics to quickly identify and resolve SMTP configuration issues.

Multi-Server Support

Works with Gmail, Office 365, SendGrid, and any custom SMTP server. Support for all major encryption protocols.

Frequently Asked Questions

Get answers to common questions about SMTP testing

What is SMTP and why do I need to test it?

SMTP (Simple Mail Transfer Protocol) is the standard protocol for sending emails. Testing ensures your email server configuration is correct and emails will be delivered successfully.

What's the difference between port 587 and 465?

Port 587 uses STARTTLS (upgrade connection after initial contact), while port 465 uses implicit TLS (secure from the start). Most modern servers prefer port 587.

Is my password stored or logged?

No. Your SMTP credentials are only used during the test connection and are never stored, logged, or transmitted to external services. All testing is done securely on our servers.

Can I test with Gmail?

Yes! For Gmail, use an app-specific password instead of your regular password. Enable 2-factor authentication and generate an app password from your Google Account settings.

What should I do if the connection fails?

Check firewall settings, verify the SMTP host and port, ensure credentials are correct, and confirm that TLS/SSL settings match your email provider's requirements.

What Users Say

Trusted by developers and DevOps teams worldwide

★★★★★

"Saved me hours debugging email issues. This tool quickly identified that I had the wrong port configured. Highly recommended!"

Sarah M. - DevOps Engineer

★★★★★

"Clean interface, fast results. Perfect for testing multiple SMTP servers during our migration. Exactly what we needed."

Marcus K. - Backend Developer

★★★★★

"The detailed error messages are incredibly helpful. No more guessing what's wrong with email configs!"

Lisa T. - SysAdmin

★★★★★

"Best SMTP testing tool I've used. Simple, reliable, and gets the job done without unnecessary complexity."

James R. - Full Stack Developer