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
Understand DMARC adkim=r relaxed default subdomain matching. Learn how it affects deliverability, alignment, and email verification accuracy with.
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Learn how to verify Apple Hide My Email temporary addresses with accuracy. Ensure inbox placement and reduce bounces with MailTester’s real-time API and.
Decode the X-Spam-Status header line by line. Learn how spam filters evaluate your email and how to improve inbox placement with real verification tools.
Prepare for basic authentication deprecation in Exchange Online. Learn how it affects your email sends and use MailTester’s real-time API to verify list.
Prevent sending from being blocked during A/B testing of email authentication settings. Use verified data and inbox placement tests to maintain sender.
Detect bulk email generation at the SMTP gateway in real time. Stop spam traps, improve sender reputation, and avoid blocklists with precise verification.
Remove outdated app passwords from Microsoft 365 with a secure, automated script. Prevent security risks and streamline access control in your.
Combat inbox placement challenges as a new sender with proven email deliverability solutions. Verify lists, test inboxes, and build sender reputation.
Understand why emails pass DMARC despite SPF failures. Learn the mechanics, common causes, and how to fix deliverability issues with real verification.
Discover why sandbox testing fails to predict real inbox placement. Learn how MailTester’s deliverability testing gives accurate, actionable insights for.
Learn how to securely delegate DKIM signing to third-party email providers using CNAME records.
Compare DMARC tree walk and traditional public suffix list methods. Learn how each impacts email deliverability, sender reputation, and inbox placement.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
