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.
Bounce codes and SMTP errors explained
Control your email warm-up pacing using real MTA domain throttle data. Avoid bounces, spam traps, and reputation damage with proven verification and delivery te
Read article →
Clean your list with accurate email verification to lower spam complaints and improve deliverability in Gmail. Use real-time API and inbox tests.
What deliverability is, why campaigns fail to arrive and the practices that keep newsletters and transactional mail in the inbox.
Verifying addresses, removing spam traps, catch-alls and disposables to protect placement.
Real-time monitoring, dashboards, KPIs, inbox rate vs delivery rate and automated alerts.
Legal requirements that affect deliverability and sending practices.
Domain vs IP reputation, warm-up plans, dedicated vs shared IPs, throttling and complaint control.
Decoding 4xx/5xx responses, hard vs soft bounces and fixing the root cause.
Setting up, tuning and reading reports for every authentication protocol.
Pre-send testing workflows: spam score, seed tests, inbox placement tests, rendering / dark-mode / accessibility checks, audits and how to read the results.
Choosing and using deliverability testing software: spam score checkers, testers, seed-list platforms and checkers.
Keeping outbound domains healthy: warm-up, volume ramp, outreach tool settings and placement tests.
Stay sharp
Occasional, practical notes on verification and inbox placement. No spam — we'd be embarrassed.
