Online SMTP Test
Test your SMTP server connection and email sending functionality instantly.
Our free SMTP Test tool allows you to check the connection to your mail server (SMTP relay). Verify your host, port, and security settings to ensure your email sending is working correctly and troubleshoot common delivery failures. Test your SMTP server now!
Quick Setup - Common Providers
Click a provider to automatically fill in SMTP settings
SMTP Server Configuration
Understanding SMTP Configuration
What is SMTP?
SMTP (Simple Mail Transfer Protocol) is the standard protocol for sending emails across the internet. It's used by email clients and applications to send outgoing mail through an email server.
Handles outgoing email delivery
Requires authentication for security
Supports encryption (TLS/SSL)
SMTP Ports Explained
Port 25
Default/unencrypted - Often blocked by ISPs
Port 465
SSL encryption - Implicit TLS from start
Port 587 Recommended
TLS encryption - Modern standard, best compatibility
Encryption Methods
TLS (Transport Layer Security)
Modern encryption standard. Starts unencrypted then upgrades to encrypted connection (STARTTLS).
SSL (Secure Sockets Layer)
Older encryption method. Connection is encrypted from the start. Still widely supported.
None
⚠️ Unencrypted - Not recommended. Credentials sent in plain text.
Provider Tips
Gmail: Requires App Password (not regular password). Enable 2FA first, then create App Password in Google Account settings.
Yahoo: Also requires App Password. Generate one at account.yahoo.com → Security.
Office 365: Use your full email as username and regular password (unless MFA enabled).
SendGrid/Mailgun: Use API key as password. Find it in your provider's dashboard.
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