Free tools
Every one of these reads public records and answers in a few seconds. No account, no email address, and nothing about the domain you type is stored.
Look up a domain's DMARC record and read what it actually tells receiving servers to do.
Read a domain's SPF record and count its DNS lookups against the limit of ten.
Check when a certificate expires, who issued it, and whether it covers the hostname.
See what status code a domain returns, whether it forces HTTPS, and which security headers it sends.
Find out when a domain expires, who it is registered with, and whether the transfer lock is on.
Read a domain's CAA records, and check the zone's nameservers against the registry's.
Or run every check at once: check a domain.