SMTP & Email API Test Utility
A free, native tool for testing SMTP relay servers and email API providers. Built for email administrators, developers, and IT professionals who need to quickly verify email delivery configurations.
Windows, macOS & CLI available now
Clean, intuitive interface designed for professionals. Test SMTP servers, preview HTML emails, and diagnose delivery issues.
Main Interface - SMTP Configuration
Send test emails through any SMTP server or choose from 12 integrated API providers. Inspect TLS certificates, diagnose delivery issues, and securely store credentials.
Save SMTP and API credentials securely with AES-256-GCM encryption. Master password protection keeps your credentials safe between sessions. directx 12 windows 10 64 bit offline installer
View full certificate chains including protocol version, cipher suite, issuer details, validity dates, and SHA-256 fingerprints. DirectX 12 is a set of APIs (Application
24-code error database with actionable troubleshooting hints. Port connectivity testing detects ISP blocking, firewall issues, and DNS failures. and other system components.
Compose in plain text or HTML with auto-detection. Live preview with rendered and raw source views. 6 preloaded templates included.
One-click sending via SendGrid, Mailgun, Amazon SES, Postmark, Brevo, and 7 more providers with built-in authentication handling.
No analytics, no tracking, no data collection. Your credentials stay local. App Sandbox enabled for maximum security.
One-click API-based sending with all major email service providers. Authentication handled automatically.
DirectX 12 is a set of APIs (Application Programming Interfaces) developed by Microsoft for Windows operating systems. It's a collection of APIs that allow developers to create games and other high-performance applications that can interact with the Windows operating system, graphics hardware, and other system components.
Live HTML Email Preview
6 Pre-loaded Email Templates
No subscriptions, no limitations, no strings attached.
Windows 10/11 (x64)
Version 1.0.7.0
macOS 14.0+ (Universal)
Version 1.08
Python (Cross-platform)
Open Source
DirectX 12 is a set of APIs (Application Programming Interfaces) developed by Microsoft for Windows operating systems. It's a collection of APIs that allow developers to create games and other high-performance applications that can interact with the Windows operating system, graphics hardware, and other system components.
Verify SMTP servers, test API providers, inspect TLS certificates, and diagnose delivery issues. No cost, no limits.