Advanced SMTP Mail Server Tester
Configure and test your SMTP server with advanced options including encoding, priority, timeouts, and delivery notifications
Advanced SMTP Mail Server Tester
Test your SMTP mail server configuration with advanced options. Configure encoding, priority, timeouts, delivery notifications, and more to ensure reliable email delivery.
Popular SMTP Providers
Common SMTP settings for major email providers
G
Gmail
Host: smtp.gmail.com
Port: 587 (TLS) or 465 (SSL)
Security: SSL/TLS Required
Timeout: 20000ms recommended
Note: Requires app-specific password
O
Outlook
Host: smtp-mail.outlook.com
Port: 587
Security: STARTTLS
Encoding: UTF-8 supported
Works with Hotmail, Live, Outlook
Y
Yahoo
Host: smtp.mail.yahoo.com
Port: 587 or 465
Security: SSL/TLS
Priority: All levels supported
Requires app password for 2FA accounts
O
Office 365
Host: smtp.office365.com
Port: 587
Security: STARTTLS
Delivery Notifications: Supported
Business and enterprise accounts
A
Amazon SES
Host: email-smtp.region.amazonaws.com
Port: 587, 465, or 25
Security: TLS/SSL
HTML Support: Full HTML formatting
Region-specific hostnames
M
Mailgun
Host: smtp.mailgun.org
Port: 587, 465, or 25
Security: TLS/SSL
Custom Timeout: Configurable
API key as password
S
SendGrid
Host: smtp.sendgrid.net
Port: 587 or 465
Security: TLS/SSL
Username: "apikey"
Frequently Asked Questions
Everything you need to know about SMTP testing
About SMTP Testing
What is SMTP testing?
SMTP testing verifies that your mail server configuration is working correctly by attempting to send a test email. It checks connectivity, authentication, and email delivery capabilities.
Why should I test my SMTP configuration?
Testing ensures your applications can send emails reliably. It helps identify configuration issues before they affect your users and prevents email delivery problems in production environments.
Security & Privacy
Is it safe to enter my email credentials?
Our SMTP tester uses secure HTTPS connections and doesn't store your credentials. However, for production accounts, we recommend using app-specific passwords or test accounts rather than your main password.
What should I use for app-specific passwords?
For Gmail, Yahoo, and other providers with 2-factor authentication, generate an app-specific password in your account settings. This provides secure access without using your main account password.
Advanced Options
What are the advanced SMTP options?
Advanced options include body encoding (UTF-8, ASCII, Unicode), message priority (Low, Normal, High), custom timeouts, HTML formatting, delivery notifications, and authentication methods for fine-tuned control.
When should I use HTML body format?
Enable HTML body format when your email content includes HTML tags, styling, or formatting. Disable it for plain text emails to ensure proper rendering across all email clients.
What timeout should I set?
Default timeout is 20 seconds (20000ms). Increase for slow networks or servers, decrease for faster response requirements. Range: 1-120 seconds.
What are delivery notifications?
Delivery notifications (DSN) are automatic emails sent back to you confirming whether your email was delivered successfully or failed. When enabled, you'll receive status reports, but note that many providers (Gmail, Outlook) don't support this feature and may ignore these requests.
Types of delivery notifications:
- Success Notifications: Confirms your email was delivered successfully to the recipient's mailbox
- Failure Notifications (NDR): Reports when your email could not be delivered due to invalid addresses, full mailboxes, or server issues
- Delay Notifications: Informs you when email delivery is delayed but still being attempted by the server
Note: These notifications are most commonly supported by enterprise email systems like Microsoft Exchange, but are often ignored by consumer email providers to reduce spam and system load.
Troubleshooting
What if my SMTP test fails?
Common issues include incorrect host/port settings, wrong credentials, disabled SMTP access, or firewall restrictions. Check your email provider's SMTP documentation and ensure all settings match exactly.
Which ports should I use?
Port 587 (STARTTLS) is recommended for most providers. Port 465 uses SSL, and port 25 is often blocked by ISPs. Always enable SSL/TLS encryption for secure email transmission.
What encoding should I choose?
UTF-8 is recommended for international characters and emojis. ASCII for basic English text. Unicode for multi-language support. UTF-32 for extended character sets.
Security Notice
This tool tests SMTP connectivity without storing your credentials. All data is transmitted securely over HTTPS. For production systems, always use dedicated SMTP credentials or app passwords.