Techniques are described for updating resources provided to a user device, using subscription based polling. A user device may send initial requests for resource to a server, each initial request including a resource identifier and a subscriber identifier. In some cases, the subscriber identifier may uniquely identify the communication session. The server maintains subscription information correlated with the subscriber identifier, the subscription information listing which resources the user device has requested and which versions of the resources are currently available on the user device. Updates to the subscribed resources may then be provided to the user device in response to a request for updates that specifies the session identifier but that may not specify the particular subscribed resources.