Adding a user alias domain or secondary domain to Google Workspace

If you manage several companies, brands or teams, each with its own domain name, you can link those extra domains to a single Google Workspace or Cloud Identity account. Depending on what you need, you add a domain as a user alias domain or as a secondary domain. In this article, we explain the difference and walk you through the procedure step by step.

Note: domains that contain “gmail” in their name (e.g. xxgmailxx.com) are rejected by Google.

Which option should you choose?

What is a user alias domain?

A user alias domain gives every existing user an extra email address under a second domain.

Example: your company is registered under jouw-bedrijf.be (primary domain). You add ander-bedrijf.be as a user alias domain. The result:

• Every user automatically gets a second address. ann@jouw-bedrijf.be now also has ann@ander-bedrijf.be.
• Emails sent to either address arrive in the same mailbox.
• You can send from both addresses (see configuration below).
• Group addresses also automatically get a second version. info@jouw-bedrijf.be can also be reached via info@ander-bedrijf.be.

Important: the alias address may be visible to other users. If someone searches Gmail for messages from Ann, both her primary and her alias address may appear in the search results.

Large organisations: if existing Google accounts already use the domain you want to add, those accounts will be renamed automatically. First add the domain as a secondary domain to receive a list of conflicting accounts within 24 hours, and only then make the switch.

What is a secondary domain?

You use a secondary domain when another team or business unit works completely independently, with its own users and mailboxes.

Example: your primary domain is jouw-bedrijf.be. You also manage a team that works under ander-bedrijf.be. By adding this as a secondary domain:

• Both domains each have their own users.
• Each user gets a fully fledged Google Workspace account with their own mailbox.
• You pay per additional user account (aliases are free).
• You manage all domains and users from the same Admin console of the primary domain.
• You can link a user alias domain to a secondary domain (via the Directory API).
• A secondary domain can later be promoted to primary domain if you wish.

Limitations: some settings are only linked to the primary domain. For example, you cannot set a separate billing address or company logo for a secondary domain.

Adding a domain — step by step

You need the Domain settings administrator privilege.

1. Open the Google Admin console and go to Menu → Account → Domains → Manage domains.
2. Click Add a domain.
3. Enter the domain name. (If you recently removed this domain from your Workspace account, wait up to 24 hours before you can add it again.)
4. Choose the type:
   • Secondary domain → a separate user base, or in preparation for replacing the primary domain.
   • User alias domain → automatic alias addresses for your existing users.
5. Click Add domain & start verification and follow the instructions to verify ownership (usually via a TXT record in the DNS).
6. If multi-party approval is required, wait for approval first.
7. Want to use Gmail on the new domain? After verification, go back to Manage domains, find the domain and click Activate Gmail. Then follow the MX configuration.

Getting started with your new domain

With a user alias domain

As soon as the alias domain is active, users automatically receive mail at their new address in the same mailbox. To also be able to send from that address, do the following in Gmail for each user:

1. Open Gmail → Settings → See all settings.
2. Accounts and Import tab (or Accounts).
3. Under Send mail as → Add another email address.
4. Enter the name and the alias address.
5. Tick Treat as an alias.
6. Click Next Step and follow the confirmation procedure.

When composing a new message, choose the sender address you want in the From field.

Good to know about primary vs. alias addresses:

• Files can be shared with both addresses.
• Signing in to Workspace is only possible with the primary address, not with the alias.
• Documents and files are always created under the primary address.
• Google Calendar invitations are always sent from the primary address.

Is the test email to the alias still not working after 48–72 hours? Contact Kyzoe or your DNS provider to have the domain verification and MX records checked.

With a secondary domain

1. Add new user accounts using the standard procedure in the Admin console.
2. When entering the primary address, click the arrow to the right of the @ and choose the correct domain from the list.

Kyzoe tip

In most cases, we recommend starting with a user alias domain when a customer simply wants to communicate under a second brand name — no extra licence cost and automatic synchronisation of all addresses. Only when there is a separate team with its own mailboxes, calendars and files should you move to a secondary domain.

For the DNS configuration of the domain verification (TXT record) and the Gmail MX records, Kyzoe guides your customers via the hosting dashboard. Contact us for support with the verification step or with conflicting Google accounts.

Source: Google Workspace Help — Domain management. Source last updated: 1 May 2026.