free tool
Microsoft 365 tenant lookup
Before asking for Microsoft 365 admin consent, see whether the company has a tenant, where it lives and how its users sign in.
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faq
Microsoft tenant lookup: common questions
Is a tenant ID sensitive?
No. Tenant IDs are published by Microsoft for every verified domain through its OpenID discovery endpoint.
What does “federated” mean?
Users sign in through an external identity provider such as Okta, ADFS or Ping instead of directly with Microsoft.
Do you check individual accounts?
Never. We look up the domain with a placeholder name only — no real user is queried.