Entra ID Tenant Lookup

Public Tenant Lookup

Entra ID Tenant Lookup

Resolve a Microsoft Entra ID tenant by GUID or domain name. Returns organization name, default domain, cloud instance, region, issuer URL and authority endpoints — all from Microsoft's public, unauthenticated discovery endpoints.

Tenant ID or Domain

Try an example:

Lookup runs in your browser using Microsoft's public discovery endpoints. Organization name is resolved through a small Idefix-hosted Azure Function that calls Microsoft Graph on your behalf. No personal data is stored or logged.

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Tenant Information

Tenant ID —

Cloud Instance —

Cloud Type —

Tenant Region Scope —

OIDC Endpoints

Issuer —

Authorization —

Token —

Raw JSON (all endpoints)

{}

How it works

By GUID: fetches the OpenID Connect discovery document at https://login.microsoftonline.com/<tenantId>/v2.0/.well-known/openid-configuration and surfaces cloud instance, tenant region, issuer and authority endpoints.

By domain: additionally queries GetUserRealm.srf which returns the organization's FederationBrandName (display name), namespace type (Managed / Federated) and verified primary domain. Also detects Desktop SSO (Seamless SSO) via GetCredentialType.

Domain discovery: collects known domains from Graph (default domain), UserRealm, Autodiscover (GetFederationInformation), and probes well-known Microsoft-generated patterns (*.onmicrosoft.com).

DNS service detection: checks MX, SPF, DMARC, DKIM, SRV, and CNAME records via DNS-over-HTTPS to detect which Microsoft 365 services (Exchange Online, Teams, Intune, etc.) are configured for each domain.

Worldwide (Commercial): login.microsoftonline.com
US Government (GCC High / DoD): login.microsoftonline.us
China (operated by 21Vianet): login.partner.microsoftonline.cn

Julian Rasmussen