An application may support the use of a plug-in. A plug-in may have an associated cache. The application may allow the plug-in to intercept network requests. The plug-in can determine if a network request is for an already-cached resource and provide the resource as a response to the intercepted network request. Additionally or alternatively, the application may allow the plug-in to make network requests. The plug-in can make a network request for data in order to add the data to the plug-in's cache. The plug-in may be able to determine when the application, the system, the network, or any suitable combination thereof are idle and cause cache requests to be made during idle periods.