5 free checks per day · 20 with a free account
Check MX, SPF, DMARC, BIMI, SMTP reachability and public blocklists for a sending domain.
Enter a sending domain to start
We look up MX, SPF, DMARC and BIMI, test SMTP reachability on your own MX servers and check two public blocklists. Nothing is sent and no login is required.
The sending readiness score weighs MX (25), SPF (25), DMARC (25), DKIM (10), SMTP reachability (10) and blocklists (5). Warnings count for half.
It measures whether the domain is technically set up to send. It is not an inbox-placement score: engagement, complaint rate, sending volume and mailbox history still decide where mail lands.
DKIM keys live under a selector only your provider knows (for example google or selector1). A failed guess does not mean DKIM is missing — use the DKIM checker with your real selector.
Error code guides
Resources
Quick reads to help you plan audiences, sending volume, sequences and measurement before launch.
Email marketing
What is mailing, how does it work, and how is it different from email marketing? Learn the fundamentals, use cases, and best practices for professional mailing campaigns.
Deliverability
Understand permanent and temporary email delivery failures and how each should affect future sending.
Sending volume
Scale a campaign with mailbox pools, individual limits, shared suppression and clear operational ownership.
From checks to campaigns