In some implementations, a computing system can perform crowd sourced access point mapping using privacy preserving techniques. For example, a server device can receive access point data reports from multiple user devices that includes various attributes and/or measurements with respect to access points with which the user devices have established connections. The access point data reports can be delivered without identifying the user devices, or users thereof, and their exact locations. Based on the access point data reports, the server device can map locations of access points and relationships between access points to generate network topologies, network locations, network quality scores, and various other characteristics of networks and/or access points. The generated access point data can be served to user devices so that the user devices can improve the efficiency of the interactions between user devices and the detected access points and/or networks.