SMTP Configuration Tester
Your Complete SMTP Testing & Troubleshooting Solution
The web's most comprehensive tool for testing, diagnosing, and understanding SMTP email configurations. Whether you're a developer, system administrator, or learning how SMTP works, we provide everything you need in one place.
What We Do
Our tool allows you to test SMTP connections in real-time with any mail server, providing detailed feedback on authentication, encryption, port connectivity, and delivery capabilities. Beyond testing, we offer the most extensive collection of SMTP knowledge resources available online.
Real-time SMTP Testing
Test connections to any SMTP server with detailed diagnostic feedback and instant results.
Multi-Provider Support
Pre-configured settings for Gmail, Office 365, Yahoo, Zoho, and dozens of other providers.
Security Analysis
TLS/SSL encryption verification, certificate validation, and authentication testing.
Debug Mode
Complete SMTP transcript analysis with HELO/EHLO handshakes, error codes, and server responses.
Cross-Platform Compatibility
Works with all major email providers and self-hosted mail servers.
Comprehensive Knowledge Base
The internet's most extensive SMTP reference library with guides and troubleshooting resources.
Our Knowledge Base
We maintain the internet's most comprehensive SMTP reference library, covering everything from basic concepts to advanced troubleshooting.
Core SMTP Concepts
Complete explanation of SMTP handshake process, ports guide, and encryption methods with real examples.
Authentication & Security
SMTP authentication methods, TLS troubleshooting, and security best practices including SPF, DKIM, DMARC.
Provider-Specific Guides
Complete setup instructions for Gmail, Microsoft 365, Yahoo, Zoho and other major email providers.
Server Administration
Postfix, Exim, cPanel SMTP configuration with examples and self-hosted mail server guides.
Troubleshooting & Diagnostics
SMTP error codes reference, connection issues, delivery problems, and DNS reputation management.
Reference Materials
SMTP glossary, code examples in multiple languages, and industry best practices.
Who Uses Our Platform
Developers & Engineers
Validate SMTP integrations during development and troubleshoot production email issues.
System Administrators
Maintain mail server health and resolve delivery problems with diagnostic capabilities.
Email Marketers
Verify SMTP configurations for transactional email services and troubleshoot delivery issues.
Students & Educators
Learn how email protocols work at a technical level with comprehensive guides.
IT Support Teams
Reference troubleshooting guides to quickly resolve user email problems.
Our Commitment to Privacy & Security
We take the security of your SMTP credentials seriously with multiple layers of protection.
Client-Side Processing
All credential validation and testing occurs client-side in your browser
TLS Encryption
All connections to mail servers use encrypted TLS/SSL protocols
No Credential Storage
We never store your usernames, passwords, or authentication tokens
Anonymized Logging
Our logs redact all personally identifiable information
Rate Limiting
Built-in abuse prevention protects our service and target mail servers
Data Protection
No sale or sharing of user data, minimal retention of anonymized logs
Get Started Today
Ready to test your SMTP configuration? Use our testing tool or browse our comprehensive knowledge base to learn more about SMTP protocols, troubleshooting, and best practices.
Start Testing Now