Microsoft Graph Contracts
Microsoft Graph Contracts is a read-only API in Microsoft Graph that lets Microsoft 365 partners (such as CSP/resellers) discover and list the customer tenants they have a relationship with. It returns each customer’s key directory identifiers and metadata—like tenant (customer) ID, default domain name, display name, and the relationship/contract type—so partner apps can enumerate customers, scope operations per tenant, and obtain tokens targeted at the right directory.