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.
Anti-spam laws and compliance: CAN-SPAM, GDPR, CASL
Understand the difference between GDPR right to erasure and suppression lists. Learn how to comply without compromising deliverability.
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Learn how many email relay hops Gmail deems excessive and how to fix delivery issues. Use MailTester’s real-time API and inbox placement tests to verify.
Discover how pipelining accelerates email verification. See how MailTester processes bulk lists efficiently without sacrificing accuracy.
Prevent header injection replay attacks by understanding DKIM oversigning. Learn how DKIM h tag oversigning strengthens email security and reduce.
Secure your email delivery with real-time certificate expiry monitoring for TLS and MTA-STS compliance.
Discover how long SURBL and URIBL delisting actually takes in 2026. Learn the real timelines, common delays, and how to verify your sender reputation.
Fix SPF permerror include domain has no SPF record issues. Verify your SPF setup and prevent email delivery failures with real-time checks and accurate.
Discover why DMARC forensic reports only include message headers — not body — and how to use this data for sender reputation and deliverability.
Secure university email domains with correct SPF and DKIM configuration. Reduce bounces, improve deliverability, and verify domains with real-time tools.
Fix inbox placement issues by understanding Google Workspace inbound gateway settings and SPF alignment.
Understand what a sender reputation score means, how it impacts inbox placement, and how to improve it with real email verification and deliverability.
After a marketing campaign breach, isolate transactional email streams with proven steps. Clean your list, verify addresses, and restore sender.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
