Various methods and systems for facilitating network traffic monitoring in association with an application running on a client device are provided. In this regard, aspects of the invention facilitate monitoring network traffic being transmitted to and/or from a client device, such as a mobile device, so that network performance can be analyzed. In various implementations, packet headers of data packets are read to obtain or extract desired network metrics that indicate network performance. Packet headers are generally read to the extent necessary to identify various network data. As such, by avoiding examination of a packet payload and, in some cases, examination of the entire header, the efficiency of monitoring network traffic at a client device is improved.