Microsoft Entra ID is Microsoft's cloud-based identity and access management service. It's what lets your organization manage who can sign in and what they can access across Microsoft 365, Azure, and thousands of third-party apps. Core Capabilities User management Create and manage user accounts, assign licenses, and control access to resources Single Sign-On (SSO) One set of credentials to access Microsoft 365, Azure, Salesforce, and thousands of SaaS apps Security and MFA Multi-factor authentication, Conditional Access policies, and risk-based sign-in protection App integration Register your own applications and configure OAuth 2.0 / OIDC authentication flows What Is a Tenant? A tenant is your organization's dedicated instance of Microsoft Entra ID. Think of it as your company's private directory in the cloud. When your organization signs up for any Microsoft cloud service (Microsoft 365, Azure, Dynamics 365), a tenant is automatically created for you. Each tenant is completely isolated from other tenants. Your users, groups, applications, and policies exist only within your tenant. Other organizations can't see or access your directory. What Is a Tenant ID? Every tenant has a unique identifier called a tenant ID — a GUID (Globally Unique Identifier) that looks like this: This ID never changes, even if your organization renames its domain. It's used in API calls, app registrations, authentication URLs, and configuration settings throughout the Microsoft ecosystem. You might also see it referred to as a "Directory (tenant) ID" in the Azure portal. Explore your organization's tenant Enter your organization's domain name or tenant ID to see its public tenant information. Azure AD vs. Microsoft Entra ID: What Changed? In July 2023, Microsoft renamed Azure Active Directory (Azure AD) to Microsoft Entra ID. Here's what actually changed and what stayed the same: The name: "Azure Active Directory" → "Microsoft Entra ID" Portal branding and documentation references SKU names: "Azure AD Free/P1/P2" → "Microsoft Entra ID Free/P1/P2" PowerShell: the AzureAD module was deprecated in favor of Microsoft Graph PowerShell What stayed the same

All functionality, features, and capabilities Tenant IDs, app registrations, and all existing configurations Microsoft Graph API endpoints and permissions Login URLs ( login.microsoftonline.com ) Pricing tiers and licensing structure In short: it's a rebrand, not a new product. If you see "Azure AD" in older documentation, it refers to the same service now called Microsoft Entra ID. Real-World Examples Small business A 50-person company subscribes to Microsoft 365 Business. Their Microsoft Entra ID tenant manages employee accounts, enforces MFA, and provides SSO to Microsoft 365 apps plus third-party tools like Slack and Zoom. Enterprise A global enterprise uses Microsoft Entra ID P2 with Conditional Access policies, Privileged Identity Management, and Identity Protection. They have B2B guest access configured for partners and B2C tenants for customer-facing apps. Developer A developer registers a multi-tenant app in Microsoft Entra ID to allow users from any organization to sign in. Their app uses the tenant ID in OAuth 2.0 token requests to direct authentication to the correct tenant. Frequently Asked Questions Is the tenant ID a secret? No. The tenant ID is publicly discoverable through Microsoft's OpenID Connect endpoints. It's not a security credential and cannot be used to gain access to your directory. Can an organization have multiple tenants? Yes. Some organizations maintain separate tenants for production, development/testing, or different business units. Mergers and acquisitions also commonly result in multiple tenants. What's the difference between a tenant ID and a subscription ID? A tenant ID identifies your Microsoft Entra ID directory. A subscription ID identifies an Azure billing subscription. One tenant can have multiple subscriptions, but each subscription belongs to exactly one tenant. Is Microsoft Entra ID the same as on-premises Active Directory? No. Microsoft Entra ID is a cloud-native identity service, while Active Directory Domain Services (AD DS) is an on-premises directory. Many organizations use both, synchronizing identities with Microsoft Entra Connect. How to find your tenant ID 5 methods including portal, CLI, and PowerShell Tenant ID to domain Identify an organization from a tenant ID GUID