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Domain Tenant Lookup: find the tenant that holds a domain.

Enter a domain to see whether a Microsoft Entra tenant has claimed it, how that tenant signs users in, and its tenant ID, cloud and region. Useful when a custom domain will not verify because another tenant already holds it. Free, with no sign-in.

Paste a domain, an email address or a URL. It is reduced to the domain name before the lookup, and a leading www. is removed.

What the results mean

  • Managed: a Microsoft Entra tenant has claimed the domain and signs users in itself.
  • Federated: a tenant has claimed the domain and sends sign-in to an external identity provider, such as AD FS. The provider address is shown as plain text, not as a link.
  • Unknown: no tenant claims the domain and no tenant ID came back, so it is free to verify.
  • Other cloud: the worldwide lookup returned Unknown, but Microsoft named a tenant for the domain in a national cloud, such as US Government. The domain is claimed there.
  • Inconclusive: the lookup failed, returned something unexpected, or the two lookups disagreed, for example no realm match but a tenant ID in the worldwide cloud. Try again in a moment.

The organisation name and the identity provider address are set by whoever runs the tenant. Treat them as clues, not as proof of who owns it.

The cloud shows where the tenant lives: the worldwide commercial cloud, US Government, or China operated by 21Vianet. The region code is shown exactly as Microsoft reports it. Microsoft documents it only as the region of the tenant and does not publish the list of possible values.

Prefer PowerShell?

The same realm lookup runs from any PowerShell session, with no module and no sign-in:

// powershell
Invoke-RestMethod "https://login.microsoftonline.com/[email protected]&json=1"

For the tenant ID, cloud and region in one step, and a comparison between two domains, use Get-DomainTenant.ps1 from the entra-domain-tenant-release repository on GitHub. The repository also walks through releasing a domain from a tenant you administer.

For the real release behind this tool, from the lookup that returned my own name to a forceDelete that was accepted and still failed, read Domain already added to another Microsoft 365 organisation: find the tenant and release it.

Privacy

When you run a lookup, your browser sends the domain names you entered to this site's lookup service. The service queries two public Microsoft sign-in endpoints, getuserrealm.srf and the tenant's OpenID configuration document, and returns a short summary to your browser. Microsoft receives the request from this site's service, not from your browser. The lookup code on this site does not log or store the domains you enter.

Disclaimer

Results are what Microsoft's public endpoints return at the moment of the lookup. getuserrealm.srf is not formally documented by Microsoft, so its fields can change without notice. Confirm in the Microsoft Entra admin center before you act on a result.