The Blog
Hard-won lessons on email verification, inbox placement, and keeping your sender reputation spotless — from the team that's been verifying email since 2000.
Anti-spam laws and compliance: CAN-SPAM, GDPR, CASL
Secure your Microsoft 365 environment by removing app passwords to meet SOC 2 compliance. Use MailTester to verify and clean your email list for better.
Read article →
Understand how greylisting and SPF/DKIM authentication affect deliverability. Use MailTester to verify email health and avoid bounces.
Discover why your emails are being quarantined in Google Workspace. Learn how to diagnose and fix deliverability issues with real-time verification and.
Resolve SMTP encoding mismatches that cause garbled content. Use real-time verification and inbox testing to catch issues before sending.
Test inbox placement per stream with MailTester’s real-time deliverability testing. Verify your campaigns before send and improve inbox delivery with.
Understand what 'SMTP queued mail for delivery' means, why emails stay in queue, and how to fix delivery delays.
Ensure inbox placement in Germany with GDPR-compliant email practices. Learn how Impressum, spam filters, and sender reputation impact deliverability.
Ensure your sending IPs are correctly named with proper reverse DNS (PTR) records. Avoid bounces and spam filters with accurate RDNS naming conventions.
Learn how to retire a sending domain without damaging your sender reputation. Use real-time verification and inbox placement tests to verify your list.
Understand Gmail's SMTP, API, and UI sending limits in 2026. Avoid bounces, improve deliverability, and reduce wasted sends with verified lists.
Discover how email verification tools using IMAP check actual inbox content for deliverability.
Learn how automatic unsubscribe agents reduce spam risk, avoid blacklisting, and improve deliverability with real-time verification and clean list.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
