One or more computing devices, systems, and/or methods for generating a recommendation for increasing loading time performance of a target webpage are provided. For example, a third party window, specifying a target webpage as a source, is inserted into a webpage. The webpage is provided to a browser that displays the webpage and loads the target webpage into the third party window. Resource timing data, associated with loading the target webpage into the third party window, is retrieved. Loading time performance of the target webpage is measured based upon the resource timing data. A recommendation for increasing loading time performance of the target webpage is generated. In an example, an action such as a resource allocation change for hosting the target webpage, compression of an image of the target webpage, a connection reduction of files connected to by the target webpage, etc. is performed based upon the recommendation.