Free tool
Free catch-all tester
Check any address at the domain. The result reports whether it accepts everything.
How this works
Catch-all detection works by asking the mail server about an address that certainly does not exist — a random local part nobody would ever have registered. If the server accepts that, it accepts everything, and no positive result from that domain means very much.
Enter any address at the domain you are curious about. The result includes a catch-all field, because it changes how the rest of the answer should be read: on a catch-all domain, "deliverable" means the domain accepts mail, not that this person exists.
This is where citations do the work verification cannot. An address published on the company's own team page, still there today, attributed to a named person, is strong evidence regardless of what the mail server would accept.
Questions, answered.
What is a catch-all email domain?
A domain configured to accept mail for every address at it, whether or not the mailbox exists. Mail to a nonexistent address is delivered to a catch-all inbox instead of being rejected.
How do you detect a catch-all domain?
By asking the mail server about an address that certainly does not exist — a random local part nobody would have registered. If the server accepts it, it accepts everything, and no result from that domain can distinguish a real mailbox from an invented one.
Why does catch-all matter for email verification?
Because it is the single largest source of false confidence in this category. On a catch-all domain, "the server accepted this address" means the server accepts all addresses. A verifier that reports that as valid without saying so is overstating what it actually found out.
Should I email addresses on a catch-all domain?
With more care than usual. The address may be real, but you have no verification evidence that it is — so weight it by other signals: whether it was published on the company's own site, whether the name matches the local part, and how recently the source page confirmed it.
Is a catch-all domain a sign of a bad list?
No. Catch-all is a legitimate and fairly common configuration, particularly at smaller organisations. It just means verification tells you less there, and provenance has to do more of the work.