A partner API is a tool for facilitating business-to-business interactions and is only accessible to carefully chosen and authorized outside developers, or API consumers. For instance, a partner API can link the internal customer data system with those outside CRM firms if a company only wishes to exchange specific customer data with them. No other API use is allowed.

Partners can access such APIs with licenses and clear rights. Partner APIs typically include greater processes for authentication, authorization, and security because of this.