Catch-all email
A catch-all (or accept-all) email domain is configured to accept mail sent to any address at the domain, even non-existent mailboxes, rather than rejecting unknown recipients. This makes it impossible for a verifier to confirm whether a specific address truly exists.
How it works
The server returns 'accepted' for every recipient at the domain. A verifier therefore can't distinguish a real mailbox from a typo, so it classifies the address as catch-all / risky rather than valid.
Why it matters
Catch-all addresses can still bounce after acceptance, and a list heavy with them inflates apparent deliverability while quietly raising real bounce risk. They need a sending strategy, not blind trust.
How Autocloz handles it
Autocloz flags catch-all and risky addresses during verification so you can segment them, send conservatively, and watch their bounce behaviour rather than treating them as fully validated.
Free tools for this
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FAQ
Should I email catch-all addresses?
Cautiously. Isolate them into a separate, low-volume segment, monitor bounces closely, and remove any that bounce. Don't mix unverified catch-alls into your main warmed sending.
Related terms
Mailbox warmup is the practice of gradually increasing a new email account's sending volume while generating positive engagement (opens, replies, moving mail out of spam) so mailbox providers build trust in the sender before real campaigns ramp up.
Sender reputation is the trust score mailbox providers assign to your sending domain and IP based on how recipients react to your mail — opens, replies, spam complaints, bounces and spam-trap hits. A high reputation lands you in the inbox; a low one routes you to spam or blocks you.
Email bounce rate is the percentage of sent emails that are returned undelivered. Hard bounces are permanent (invalid or non-existent address); soft bounces are temporary (full mailbox, server down). A high bounce rate signals a poor list and damages sender reputation.
A spam trap is an email address operated by mailbox providers and blocklist operators specifically to catch senders with poor list hygiene. There's no real person behind it, so any mail it receives indicates you're emailing addresses you didn't earn permission to contact.