In one embodiment, a device classification service assigns a set of endpoint devices to a context group. The device classification service forms a context summary feature vector for the context group that summarizes telemetry feature vectors for the endpoint devices assigned to the context group. Each telemetry feature vector is indicative of a plurality of traffic features observed for the endpoint devices. The device classification service normalizes a telemetry feature vector for a particular endpoint device using the context summary feature vector. The device classification service classifies, using the normalized telemetry feature vector for the particular endpoint device as input to a device type classifier, the particular endpoint device as being of a particular device type.