TL;DR
A catch-all domain accepts all incoming emails, even if the specific inbox doesn't exist.
Catch-all addresses are labeled Risky in ListKit, not Bad.
They are not automatically unsafe — many perform fine in campaigns.
Best practice is to segment them separately if deliverability is a top priority.
When you'd use this / Why it matters
If you've noticed Risky results in your verification CSV, most of them are likely catch-alls. Understanding what a catch-all is helps you decide with confidence whether to include these addresses in your outreach.
What is a catch-all email address?
A catch-all domain is configured to accept every email sent to it, regardless of whether the specific mailbox actually exists. For example, if the domain acme.com is set up as a catch-all, any address at acme.com is accepted by its mail server, even one that was never created.
This makes catch-alls difficult for verification tools to confirm with certainty, because the mail server itself won't reject an invalid address the way it normally would.
Should I send to catch-all addresses?
Yes, with some awareness. Catch-alls are not the same as invalid or Bad addresses. In most cases, the email genuinely exists and is being received — the domain setup just makes it harder to verify with 100% certainty.
You can:
Include catch-all (Risky) addresses in your campaigns if you want maximum reach
Treat them with slightly more caution than Good addresses
Best practices for catch-all addresses
A 2-4% bounce rate is typical, and bounce rate alone is not a problem while your positive replies are healthy. If positive replies start to fall, check your bounce rate and consider leaving catch-all addresses out of your next export.
Segment them separately: If deliverability is extremely sensitive, run catch-alls in their own campaign rather than mixing them with Good addresses
Test before scaling: Send to a smaller batch of catch-alls first and monitor bounce and reply behavior
Don't automatically exclude them: Removing all catch-alls can significantly shrink your list without a proportional gain in deliverability
Monitor performance over time: If catch-alls in a specific campaign are bouncing heavily, reduce reliance on that domain type going forward
Expected outcome
You should now be able to:
Define what a catch-all email address is
Decide with confidence whether to include catch-alls in your campaigns
Apply best practices to minimize risk while maximizing list volume
Troubleshooting / FAQs
Are catch-alls the same as Bad emails?
No. Catch-alls are labeled Risky, not Bad. They are not confirmed invalid.
Will sending to catch-alls hurt my domain reputation?
Not inherently. Follow the best practices above (segmenting, testing) to manage any added uncertainty.
Why can't ListKit just confirm catch-alls definitively?
The mail server itself accepts all addresses at that domain, so there's no way to technically distinguish a real mailbox from a nonexistent one through standard verification.