tenantid

Tenant ID, or tenant identifier, is a unique label assigned to a tenant in a multi-tenant software environment. A tenant represents a distinct group of users, data, and configuration within a shared instance of an application or service. The tenant ID is used to isolate data, route requests, and enforce access policies between tenants.

Commonly the tenant ID is a globally unique value such as a GUID (for example 123e4567-e89b-12d3-a456-426614174000). In some platforms the tenant is also named via a domain-like string (such as contoso.onmicrosoft.com or a customer domain) but the underlying identifier is often the GUID. In authentication flows, the tenant ID is frequently embedded in tokens or used in authority URLs (for example to target a specific directory in OAuth 2.0/OpenID Connect).

Use cases include SaaS applications serving multiple customers, organizational directories in cloud identity services, and data isolation in service APIs. When a request is processed, the system uses the tenant ID to determine the data boundary and apply policies for that tenant.

Security considerations: tenant boundaries must be maintained; tokens should include the tenant_id claim; tokens must be protected; misconfigurations can leak data between tenants.