Microsoft Dynamics CRM Web API is a feature available to Microsoft Dynamics CRM Online organizations that use Dynamics CRM Online 2015 Update 1. The API uses HTTP methods, JSON for requests/returns, and implements the ADAL API to manage OAuth2 authentication. Developers should note that this API is a preview feature and is currently unsupported. Use the Microsoft Dynamics CRM Web API to manage and query entities, or call unbound functions and actions. See the extensive API documentation for a full description of the API's current capabilities, code samples, and sample API implementations.