What is a catch-all domain?
A catch-all (or accept-all) domain is configured to accept email sent to any address at that domain. Send to maria@company.com or to asdf1234@company.com and the server says yes to both at the moment of delivery.
Companies do this for understandable reasons: so mail to a misspelled name still reaches someone, so departing employees’ mail isn’t lost, or because their security gateway accepts everything first and sorts it out afterwards. Many business domains, especially larger ones and those behind email security gateways, work this way.
Why verifiers can’t check them
A standard verifier tries to confirm that a mailbox exists. A catch-all domain says yes to every address, so the verifier has nothing to separate a real person from a typo. The honest answer it can give is “unknown”, which is why these addresses come back as catch-all, accept-all or risky.
Some of those addresses are real people. Others don’t exist and will bounce when you send your campaign. To a standard verifier, the two look identical.
What sending to them blind costs
- Bounces hurt the domain you send from. Mailbox providers watch bounce rates. A campaign with many hard bounces signals a poorly kept list, which pushes later mail toward spam.
- Sending tools pause accounts. Outreach platforms and email service providers often pause or review accounts whose bounce rate climbs past their limits.
- Daily limits are finite. Every message to a dead mailbox uses a slot that could have reached someone who can reply.
What dropping them costs
The safe-looking alternative, deleting every catch-all address, throws away the real decision-makers among them. If you bought the data or spent time researching those contacts, you pay for them and then never use them.
How to resolve them
BounceBrake is built for exactly these addresses. Its proprietary verification resolves catch-all and unknown addresses that standard verifiers can’t settle:
- Upload the catch-all segment as a CSV, or send it through the API.
- Most lists finish within 24–48 hours, with live counts while they run.
- Each address comes back valid (safe to send) or invalid (would bounce). Anything we can’t settle within 7 days is marked unknown and the credit is returned.
Your own domains and sending accounts are never involved.
A workflow that keeps costs down
- Verify the whole list with your standard verifier. It’s fast and cheap and settles most addresses.
- Export only the catch-all, accept-all, risky or unknown rows.
- Upload that segment to BounceBrake, or send it through the API.
- Add the valid results back to your list and send.
A note on soft bounces
Hard bounces mean the mailbox doesn’t exist, and those are what list verification can catch. Soft bounces (a full mailbox, a server that’s down for an hour, a block based on your sender reputation) depend on the day and on your own sending setup. Keep authentication (SPF, DKIM, DMARC) in order and warm new domains gradually to keep those low.