An interface of a content management system manages storage and access of content on the system. For example, after receiving, from a client, a request to download a content item, the interface determines whether the request includes a valid token. If so, the interface sends a content item request to a storage service, retrieves the content item, and sends the content item to the client. Otherwise, the interface sends an authorization request to an authorization service, an authentication request to an authentication service, and a content item request to the storage service. Based on the requests, the interface determines whether the content item is available in storage and whether the client is authorized to access the content item. When the content item is available in storage and the client is authorized to access the content item, the interface retrieves the content item and sends the content item to the client.