How Google Workspace answers a verification check
A Workspace domain looks like any company domain, but its MX records point to Google: aspmx.l.google.com and the alt hosts, or the newer single smtp.google.com. Google answers mailbox checks for Workspace exactly as it does for Gmail: 250 for a real user, 550 5.1.1 for a missing one.
Two Workspace settings change the picture. Admins can route mail for unrecognised addresses to a single mailbox, which makes the domain a catch-all. And Google Groups and user aliases accept mail like a mailbox, so sales@ or team@ are often real and deliverable even though nobody owns them personally.
Google Workspace replies and what RocketVerifier returns
Each SMTP reply maps to one status and sub-status. Replies about the probing server are never counted against the address.
| Reply | Result | What it means |
|---|---|---|
| 250 2.1.5 OK | deliverable none | A user, alias or group accepts mail. Unless the domain is catch-all. |
| 550 5.1.1 The email account that you tried to reach does not exist | undeliverable mailbox_not_found | No such user, alias or group. |
| 250 for random addresses too | risky catch_all | Catch-all routing is on. Each address gets a 0 to 100 score and a verdict. |
| 421 4.7.0 / 4.7.28 rate limit | unknown blocked | About the probing IP. Not charged. |
What RocketVerifier does differently for Google Workspace
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Workspace detected from MX, not the name
Any domain whose MX points to Google is verified with Google's rules and budget, and told apart from consumer Gmail by its MX hosts.
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Live catch-all test on every domain
After the real address is accepted, random addresses at the same domain are tested in the same session. If they are accepted too, the domain is catch-all.
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A verdict for each catch-all address
Catch-all addresses are scored 0 to 100 from the provider, how plausible the local part is and the domain's learned address pattern. 65 and above is send_safe.
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Group and role addresses flagged
sales@, team@ and other shared inboxes are returned as risky with the role_based sub-status, so you choose whether to mail them.
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Hosting is never proof
Having Google MX records never makes an address deliverable on its own. Only Google's explicit answer does.
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No email is ever sent
The SMTP conversation stops at RCPT TO, before DATA. Your recipients never see a probe.
Sending to Google Workspace: what to get right
- Google's bulk sender requirements apply to personal Gmail accounts, not Workspace, but Workspace filtering rewards the same practices: authentication, low complaints, clean lists.
- For catch-all Workspace domains, send only to send_safe addresses first and widen from there based on results.
- Keep role addresses out of cold outreach. Shared inboxes complain more and convert less.
Keep reading
Sources
- Google Workspace: Gmail SMTP errors and codes
- Google Workspace Admin Help: Get misaddressed email in a catch-all mailbox
- Google: Email sender guidelines FAQ
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