Free tools
Check it now, no account needed
One target per run, a few runs an hour, and nothing you enter is stored.
Blacklist check
See whether an IP address or domain is listed on the major blocklists.
Open the toolDNS authentication check
Check SPF, DKIM, DMARC, MX and the other records mailbox providers look at.
Open the toolSMTP server check
Connect to a mail server and see its banner, TLS certificate and capabilities.
Open the toolWant it checked all the time?
A free account adds monitors, alerts, history and higher limits.