Systems and methods are provided for monitoring the performance of a network with respect to providing results for user requests. A user request can correspond to a search query, an entry of a uniform resource locator (URL) or other address for a document on a network, or another type of request. A plurality of user requests are aggregated, such as based on logs of search query or browsing activity. A representative group of user requests is selected and then submitted in order to evaluate the results provided. Based on a heuristic analysis of the results, an alert can be provided to indicate potential performance problems in the network environment.