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.
Deliverability testing inside your ESP, CRM and sending platform
Running deliverability tests with HubSpot, Mailchimp, SendGrid, Shopify, WordPress, Zapier and other tools.
Read article →Comparisons of deliverability and verification tools, alternatives and migration guides.
Provider-specific filtering rules, SpamAssassin and corporate filters, postmaster tools and checking whether mail actually lands in the inbox.
Spamhaus, UCEPROTECT, Proofpoint and other blocklists — how to check, get delisted and stay off.
Discover how panel data improves email deliverability testing. Learn what it is, why it matters, and how MailTester uses real-world inbox placement to boost sen
Understand the SpamAssassin score 5.0 threshold and how it impacts deliverability. Use MailTester’s verification API to catch risky addresses before they harm
Verify emails with 98.9% accuracy, detect bounces, and test inbox placement. Improve deliverability with real-time API and bulk checks.
Learn how TLS-RPT works and set up the _smtp._tls record for email security. Improve deliverability and compliance with real-time verification.
Boost your franchise outreach success with accurate email verification. Reduce bounces, improve deliverability, and increase reply rates using real-time validat
Learn how Fastmail's spam filters work and how to ensure your emails reach inboxes. Use real-time verification with MailTester to fix deliverability issues befo
Reduce bounce rates and boost outreach success in construction procurement with real-time email validation. Verify every address before sending.
Improve inbox placement and reduce bounces with proven email deliverability tools designed for Kajabi and similar SaaS membership platforms. Test, verify, and d
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
