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.
Email authentication: SPF, DKIM, DMARC, BIMI and MTA-STS
Evaluate your secondary domain registrar and DNS provider options to avoid deliverability risks, boost inbox placement, and protect sender reputation.
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Understand Woodpecker’s daily sending limits and how they impact deliverability. Learn how to optimize your email volume without triggering spam filters.
Prevent inbox placement issues by implementing a sunset policy that removes inactive addresses before they become recycled spam traps.
Learn how to structure mail streams by subdomain to improve deliverability, reduce bounces, and maintain sender reputation.
Find the exact cost of Amazon SES dedicated IPs per month in 2026. Learn how to reduce email delivery costs with email verification and list hygiene.
Test your email links against SURBL and URIBL blacklists with MailTester’s deliverability tool.
Learn how to set up Postmark return-path domain CNAME records correctly. Avoid bounces and protect sender reputation with step-by-step guidance.
Segment your email list by opens in the last 30 days to improve deliverability. Use real-time verification to clean and warm up 100K+ addresses safely.
Discover how mailbox providers assess sender reputation in real time. Reduce bounces, avoid spam traps, and improve inbox placement with precise email.
Check inbox delivery status for nate.com and other Korean portal email providers. Use MailTester’s bulk verification and real-time API to reduce bounces.
Stop Brevo SMTP emails from landing in spam. Diagnose root causes and apply proven fixes using real-time verification and deliverability testing.
Fix the Onet.pl 550 5.7.1 blocked by policy error with proven steps. Verify email lists, reduce bounces, and improve inbox placement using real-time.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
