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.
Sender reputation, IP warm-up and sending infrastructure
Learn how shared IP reputation impacts email deliverability, what pool reputation means, and how to verify your list’s health with real-time tools.
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Ensure a smooth dedicated IP migration with this practical checklist. Verify list quality, test deliverability, and protect sender reputation before.
Verify DMARC alignment before sending email campaigns to avoid deliverability failures. Use MailTester’s inbox-placement tests and real-time API for.
Learn how to set PTR record on DigitalOcean, Hetzner, and Vultr to improve email deliverability.
Build a resilient email delivery system with a proven on-call rotation and escalation plan. Reduce bounces, improve inbox placement, and act fast when.
Ensure your emails reach Yahoo inboxes by understanding why DMARC alignment is required — not just a DMARC record.
Ensure your emails meet the 2-second unsubscribe requirement. Fix delivery, reduce bounces, and protect sender reputation with MailTester’s email.
Resolve the 5.4.310 DNS domain does not exist error in Office 365. Use real-time verification to prevent bounces and improve deliverability.
Set up and process bounces with IMAP polling for better list hygiene. Reduce spam complaints and improve deliverability.
Stop wasting sends on recycled Yahoo addresses. Learn how Yahoo recycles deactivated emails and how MailTester catches them before they bounce.
Fix 5.7.511 banned sender errors on transactional emails. Diagnose IP reputation, verify addresses, and improve inbox placement with real-time email.
Understand how SendGrid’s shared IP infrastructure has been exploited for phishing and its real impact on sender reputation, deliverability, and list.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
