Google Workspace SMTP: smtp.gmail.com and the smtp-relay.gmail.com relay
Google Workspace SMTP settings for apps, printers and servers: smtp.gmail.com (2,000/day, app password) or the Workspace SMTP relay smtp-relay.gmail.com (10,000/day, IP allowlist or auth). Setup steps and limits.
Google Workspace outgoing mail server:
smtp.gmail.com, port <code>587</code> (STARTTLS) or <code>465</code> (SSL/TLS) or <code>25</code> (STARTTLS or none), username = user@yourdomain.com (smtp.gmail.com) — or none when the relay is allowlisted by IP, password = App Password.
Google Workspace SMTP settings at a glance
| Outgoing (SMTP) host | smtp.gmail.com (per user) or smtp-relay.gmail.com (Workspace SMTP relay service) |
|---|---|
| Ports & encryption |
587 — STARTTLS <em>(both hosts)</em>465 — SSL/TLS <em>(both hosts)</em>25 — STARTTLS or none <em>(smtp-relay.gmail.com only, from allowlisted IPs)</em> |
| Username | user@yourdomain.com (smtp.gmail.com) — or none when the relay is allowlisted by IP |
| Password | App Password (smtp.gmail.com) — or none for IP-allowlisted relay |
| Authentication | The relay service is configured by an admin in Admin console → Apps → Google Workspace → Gmail → Routing → SMTP relay service: choose allowed senders (any address in your domains or only registered users), authentication by IP range and/or SMTP AUTH, and require TLS. |
How to set up Google Workspace SMTP
- For a single app or user: follow the Gmail steps (2-Step Verification → App Password) with host smtp.gmail.com and the Workspace address as username.
- For servers, printers and scanners: Admin console → Apps → Google Workspace → Gmail → Routing → SMTP relay service → Add setting.
- Allowed senders: "Only addresses in my domains"; Authentication: add your server IP range and/or tick "Require SMTP Authentication"; tick "Require TLS encryption".
- Configure the device with host smtp-relay.gmail.com, port 587 (STARTTLS) or 465, and (if enabled) a Workspace user + App Password.
Sending limits
- smtp.gmail.com: 2,000 messages per user per day, 10,000 recipients per day; trial accounts 500/day.
- smtp-relay.gmail.com: 10,000 messages per user per day, 100 recipients per message, ~130 messages per minute; blocks for 24 h when exceeded.
- Messages must come from a domain you own in Workspace; the relay rejects other From domains unless "any address" is enabled.
Things that catch people out
- Relay changes take up to 24 hours to propagate.
- IP-only authentication needs a static, public IP; dynamic offices and most clouds must use SMTP AUTH.
- Google reserves the right to throttle bulk mail even under the cap — marketing volume belongs on a dedicated sending service.
Common Google Workspace SMTP errors
| Server reply | Meaning | Fix |
|---|---|---|
550 5.7.1 Invalid credentials for relay | The connecting IP is not in the relay allowlist and no SMTP AUTH was used. | Add the IP range in the relay setting or enable SMTP AUTH and send credentials. |
550 5.7.1 The IP you are using to send mail is not authorized | Same cause, seen on port 25. | Use 587 with AUTH, or allowlist the IP. |
421 4.7.0 Temporary System Problem | Throttling. | Slow down and retry with backoff. |
More codes: 535 authentication failed, 550 relay denied, 554 rejected as spam, connection timed out — or all SMTP error codes.
When Google Workspace is not enough for your app
When a provider caps you or blocks a port, point the same app at QueenSMTP instead: host smtp.queensmtp.com, port 587 (STARTTLS) or 465 (SSL), your SMTP username and password from the dashboard. $5/year plus $0.10 per 1,000 emails, 100 free a day to test.
Get SMTP credentials — free to test Test Google Workspace nowRelated settings
Google Workspace SMTP — questions
smtp.gmail.com sends as one authenticated user with a 2,000/day cap. smtp-relay.gmail.com is the Workspace relay service an admin enables for servers and devices, with a 10,000/day cap and optional IP-based authentication.
Yes, if the admin adds your server's public IP to the relay setting. Otherwise enable SMTP authentication and use a user's App Password.
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