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 deliverability fundamentals and best practices
Discover why UK ISP mailboxes reject email from new sending IPs and how to fix it. Use MailTester to verify sender reputation and boost inbox placement.
Read article →
Learn why marketing emails aren't accepted in Italy's PEC system and how to verify PEC addresses with MailTester’s 98.9% accurate email verification tool.
Set up a self-hosted SpamAssassin test server to evaluate spam filtering accuracy. Use real-time email verification and inbox placement testing to.
Learn what APRF is, how it standardizes email sender performance reporting, and why it matters for deliverability and list hygiene.
Fix DMARC reports showing unauthorized senders. Use real-time email verification to identify risky IPs and protect your domain reputation.
Learn how VERP and Message-ID tracking differ in identifying bounced recipients. Improve list hygiene and deliverability with accurate, real-time.
Ensure your Postfix email server passes SPF and DMARC checks. Use this verified configuration checklist to reduce bounces, avoid spam filters, and improve.
Learn how to handle 4xx deferral errors from Gmail and Yahoo using MTA backoff mode. Reduce bounces and improve inbox placement with real-time email.
Compare free DMARC report analyzers to detect email spoofing, improve sender reputation, and boost inbox placement. See how MailTester stands out.
Discover how resending to non-openers impacts deliverability. Reduce spam risk and improve inbox placement with precise email verification.
Follow this step-by-step Postmaster Tools V2 domain migration process to maintain sender reputation and prevent deliverability issues.
Decode the X-Mimecast-Spam-Score header to improve inbox placement and reduce spam complaints.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
