Is Gmail a Catch-All Domain?

What Is a Catch-All Domain?

A catch-all domain (also called an accept-all domain) is configured to accept email sent to any address at that domain - even addresses that don't exist as real mailboxes. The mail server returns 250 OK to SMTP verification probes regardless of whether the recipient is real.

This is intentional on many corporate domains - IT administrators enable it to catch typo'd email before it bounces. But it makes email verification harder: when every probe returns "accepted," you can't tell which addresses are real without actually sending.

Why Gmail Is Not Catch-All

Gmail's MX infrastructure (Google Workspace servers) returns a hard 550 5.1.1 The email account that you tried to reach does not exist for any address that has never been registered. This is a definitive rejection - not a catch-all response. Gmail can therefore be verified with 100% SMTP confidence per address.

How BounceZero Handles Catch-All Domains

When BounceZero detects a catch-all domain, it:

1. 1. Flags the result as accept_all - not verified or invalid.
2. 2. Scores the domain using ML signals: MX reputation, domain age, DMARC/SPF presence, historical engagement patterns.
3. 3. Returns a risk score so you can decide whether to send or suppress - rather than leaving you with a binary unknown.

For Gmail and all other major consumer providers, this is irrelevant - they return definitive SMTP responses for every address.