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 DKIM 1024 vs 2048 key length for email security. Learn why 2048 is now preferred and how to verify your setup with real-time tools.
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Ensure every digest reaches the inbox with verified, high-quality addresses. Reduce bounces, improve sender reputation, and boost deliverability using.
Stop relying on public suffix lists for email validation. Learn how modern tools like MailTester use real-time SMTP checks and domain intelligence to.
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.
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.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
