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.
Inbox placement by mailbox provider: Gmail, Outlook, Yahoo and spam filters
Learn how to build a reliable seed list across Gmail, Outlook, and Yahoo with proven methods. Reduce bounces, boost deliverability, and verify addresses.
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Ensure consistent inbox placement with a proven weekly seed test cadence. Use MailTester’s inbox-placement testing to monitor deliverability and fix.
Learn how to check if your emails are being quarantined in Microsoft 365. Use real-time verification to detect blocked senders and fix inbox placement.
Use Mailgun message tags to track deliverability, reduce bounces, and boost inbox placement. See how to implement and measure tag analytics effectively.
Ensure your brand logo appears in Apple Mail with MPP and BIMI. Test deliverability, verify email validity, and fix BIMI issues before sending.
Learn how Gmail defines bulk senders and counts 5000 messages per day. Prevent delivery issues with real-time verification and inbox placement testing.
Discover the real reasons your email took 15 minutes to arrive — from server delays to spam filters.
Ensure your email campaigns comply with CASL express consent rules. Learn what's required, how to collect valid consent, and avoid penalties with.
Learn how KumoMTA shaping rules and traffic shaping automation improve deliverability. Optimize email sending speed, avoid throttling, and maintain sender.
Learn how HTML comments and tracking markup impact spam scores. Reduce inbox placement issues with real inbox testing and email verification.
Learn how stream separation and DMARC reporting per stream improve email deliverability, reduce bounces, and strengthen sender reputation in 2026.
Understand the differences between IVMSIP, IVMSIP24, and IVmURI in email verification. Learn how each affects deliverability and list hygiene with.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
