The server always says yes
A catch-all server accepts every address, so a mailbox check proves nothing.
Mailcleaner · Catch-all detection
Catch-all email detection that doesn't guess.
Flaxxa Mailcleaner tests every domain it checks for catch-all behaviour. When a server accepts an address that can't exist, the address is reported as catch-all with a score, so you decide how to treat it instead of trusting a meaningless yes.
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mailcleaner.flaxxa.com / catch-all-detection
Verify
VALID[email protected]google
Risk
8
Confidence
96
Signals
- MX found
- SMTP connectable
- Disposable
- Role-based
- On Standard and above
- Tested
- A catch-all score
- Scored
- Checked fresh each time
- Never cached
- Hint to confirm
- Engagement
01 / 04
Why are catch-all addresses a problem?
Some verifiers call them valid
Passing them as valid hides real bounces until send day.
They are common in business lists
Company domains are often set up to catch misaddressed mail.
02 / 04
How does catch-all detection work?
Check the real address
The SMTP check asks the server about the address on your list.
Check an impossible one
It then asks about a random address that can't exist on that domain.
Compare the answers
If both are accepted, the domain is catch-all and the first yes carries no weight.
Report it honestly
The address gets the catch-all verdict and a catch-all score, and is never cached.
03 / 04
How can you handle catch-all results?
Filter in or out
The export lets you include or leave out catch-all addresses.
Engagement hint
Pass engaged or last_engaged_at through the API to confirm recently active addresses.
Fresh re-checks
Catch-all verdicts are never reused from the cache, so a later check looks again.
Risk score
Use the score to decide which catch-all addresses to send to first.
04 / 04
What do you gain from honest catch-all results?
Fewer bounces you didn't see coming.
No false confidence
You know which addresses are confirmed and which aren't.
Smarter sending
Send to engaged and confirmed addresses first.
Keep real people
No need to delete a whole company domain.
Keep exploring
More Mailcleaner capabilities
The checks
The checks behind each verdict: syntax, typo, disposable and role detection, MX lookup, an SMTP mailbox check, catch-all detection and deeper signals.
Email verification
Verify one email address or a whole list: a verdict, a 0–100 risk score and a confidence score for each, from a paste, a file, Google Drive or the API.
List cleaning
Clean an email list in one upload: counts per verdict, a clean CSV or XLSX export, and a suppression list so bad addresses don't creep back in.
FAQ
Catch-all detection: common questions
A domain whose mail server accepts mail for any address, whether the mailbox exists or not. Verifiers can't confirm individual mailboxes on it.
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Spin up a workspace and put Catch-all detection through its paces.
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