// tools/tenant

Tenant ID lookup

Type any domain that uses Microsoft 365 or Entra ID, such as contoso.com, to see its tenant ID, which Microsoft cloud it's in and its region scope. Useful for B2B setups, cross-tenant access and support tickets.

Lookups go straight from your browser to Microsoft or a public DNS resolver. Nothing is sent to this site.

Do it yourself in PowerShell

The tool reads the domain's public OpenID Connect configuration, which needs no sign-in:

powershell5 lines

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5$domain = "contoso.com"
$cfg = Invoke-RestMethod "https://login.microsoftonline.com/$domain/v2.0/.well-known/openid-configuration"
$cfg.issuer                 # https://login.microsoftonline.com/<tenant ID>/v2.0
$cfg.tenant_region_scope    # e.g. EU, NA, WW
$cfg.cloud_instance_name    # e.g. microsoftonline.com

Tenant IDs aren't secret: any app a user signs in to can see them. The region scope is Microsoft's broad grouping, not the exact datacentre.