Mail that can be believed
The MX records mail routes through and the SPF, DKIM and DMARC policies receiving servers check — with the full record values, not just a tick. Free, no signup, 5 checks a day.
5 free checks a day. No signup, no key.
Three records, one story
MX — where mail is routed
The MX records name the servers that accept mail for the domain, in priority order. A missing MX is why mail to the domain quietly fails with no error anyone sees.
SPF
Lists the servers allowed to send mail as the domain. A receiving server checks it before deciding whether the envelope sender is plausible. It does not stop anyone from writing your name in the visible From line — that is DMARC's job.
DKIM
Signs outgoing mail with a key published in DNS. The selector is chosen by the sender and listed nowhere a checker can enumerate, so not finding one does not prove the domain signs nothing.
DMARC
Tells receivers what to do when SPF and DKIM disagree with the From address, and where to send the reports. Without it, a failed check is advisory and nothing acts on it.