Catch-All (Accept-All)
A domain configured to accept emails sent to any address, regardless of whether the specific mailbox exists.
A catch-all domain (also called accept-all) is configured to accept all incoming emails, even if the specific recipient mailbox doesn't exist. For example, if example.com is catch-all, emails to nonexistent@example.com would still be accepted.
Why this matters for verification: Catch-all domains make it impossible to determine if a specific email address is valid through SMTP verification alone, because the server always responds "yes" during the handshake.
How SendSure handles catch-all: SendSure uses AI-powered catch-all resolution with a 54,000+ name database and multiple external signal sources (Gravatar, GitHub, HIBP, Gmail API) to determine the likelihood that a catch-all email belongs to a real person. This goes far beyond simple SMTP verification.
Best practices:
- Don't automatically remove all catch-all emails — many are valid
- Use engagement data and AI scoring to segment catch-all addresses
- Send to high-confidence catch-all addresses and monitor bounce rates
Related Terms
Email Verification
The process of confirming whether an email address is valid, deliverable, and belongs to a real person.
SMTP Handshake
The process of connecting to a mail server to verify if a specific mailbox exists, without actually sending an email.
Sender Reputation
A score assigned by ISPs to your email sending domain/IP that determines whether your emails reach the inbox.
Related Blog Posts
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