Tenant Identifier

Finding the Identifier for Azure or Office 365 Tenants

by Tony Redmond

After seeing a tweet about a site that could return the tenant identifier for any Azure or Office 365 tenant, I was a tad suspicious. After all, this data should be private - or so you'd think. In fact, the WhatIsMyTenantId.com site simply takes records available to enable OAuth 2.0 sign-ins and extracts the tenant identifier from their content. It's an easy way to get hold of tenant identifiers.