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. acdsee professional 2021 license key free
View full certificate chains including protocol version, cipher suite, issuer details, validity dates, and SHA-256 fingerprints. If you're serious about using ACDSee Professional 2021,
24-code error database with actionable troubleshooting hints. Port connectivity testing detects ISP blocking, firewall issues, and DNS failures. acdsee professional 2021 license key free
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.
If you're serious about using ACDSee Professional 2021, it's recommended that you purchase a license key from the official ACDSee website. This will ensure that you get a legitimate license key that works and provides you with access to all the features and tools.
If you own an older version, you can often sign in to your acdID account to access discounted upgrade rates.
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
If you're serious about using ACDSee Professional 2021, it's recommended that you purchase a license key from the official ACDSee website. This will ensure that you get a legitimate license key that works and provides you with access to all the features and tools.
If you own an older version, you can often sign in to your acdID account to access discounted upgrade rates.
Verify SMTP servers, test API providers, inspect TLS certificates, and diagnose delivery issues. No cost, no limits.