Verify addresses, diagnose authentication and reputation problems, monitor blacklists and fix issues with step-by-step instructions — in one toolkit.
Check single addresses, lists or CSV files: syntax, domain, MX, mailbox (over SMTP, without sending), disposable, role and catch-all detection. Unknown results are reported as unknown, never as valid.
Verify emails →SPF with lookup counting and include tree, DKIM key inspection and selector discovery, DMARC policy and alignment, MTA-STS, TLS-RPT, BIMI and DNSSEC — with the exact record to fix each problem.
Check a domain →Query 20+ DNS blocklists in parallel. Each list is health-checked first, so a list that refuses your query shows as unknown instead of "clean". Automatic monitoring alerts you by email when a listing appears.
Check blacklists →SMTP connection, banner, EHLO capabilities, STARTTLS and certificate checks on ports 25, 587 and 465, plus reverse DNS and FCrDNS. Read-only: we never log in and never send mail.
Test SMTP →Describe the symptom — spam folder, bounces, not receiving — and get a ranked fix plan built from the checks that matter for that problem.
Solve a problem →Trace a message's delivery path and authentication results from its headers, translate bounce messages into plain language, and send a real message to a test address for a Technical Deliverability Score.
Analyze headers →Check CSV lists of domains or IPs, export PDF and JSON reports, share read-only report links, and automate everything with the REST API using the same credits.
API documentation →Your first checks are free — no card needed.
