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
Fix SPF permerror syntax errors with unknown mechanisms. Learn how to identify and resolve them to prevent email delivery failures.
Read article →
Learn how to calculate spam complaint rates in Gmail vs other ESPs. Identify key differences and improve inbox placement with precise verification tools.
Create a reliable deliverability incident response playbook to reduce bounces, avoid blocklists, and restore sender reputation.
See which email blocklists truly hurt inbox placement. Rank them by real-world impact, not hype. Fix your sender reputation with data-backed insights.
Reduce false positives in email phishing detection caused by link shorteners. Clean your list, verify addresses, and improve inbox placement with accurate.
Learn the exact pace of new domain warm-up for transactional emails only. Reduce bounces, avoid spam filters, and land in inboxes with proven steps.
Navigate TCPA vs CAN-SPAM compliance for SMS and email. Learn what's legal, how consent works, and avoid penalties with real verification tools.
Understand what happens to emails that fail DMARC when p=quarantine is set. Learn how Gmail and Outlook handle them, and how to verify your list to avoid.
Learn what 'Gmail this message could be a scam' really means, how to verify risky emails, and prevent fraud with real-time email verification.
Fix the 421 4.4.2 SMTP timeout error with real-time verification and inbox placement testing. Reduce bounces and improve deliverability today.
See a real DMARC strict alignment exact domain match example. Improve inbox placement with accurate email verification and deliverability testing.
Learn how to set up a PTR record for your mail server on AWS EC2 with clear steps. Improve deliverability and sender reputation with verified reverse DNS.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
