A configuration history service for web-based computing resources is implemented by capturing and storing a historical record of each configuration state for each computing resource in a subscriber's account. Files of the configuration history store information about a computing resource type offered by the web service. The file comprises records for each particular resource of that type that is or was actively configured in the subscriber's account during the period that the configuration history service is active in the account. Each record lists a particular configuration state, at a particular point in time, for a particular computing resource. The configuration history of a computing resource can be displayed as a timeline by which a subscriber can access information describing the configuration state of the particular computing resource at any point in time.