Due to the advances on mobile technology, it is becoming feasible to host Web Services on a mobile device, making it perceived as potential data collector and provider. Hosting Web Services on mobile devices gains in importance when it comes to deliver real-time contextual data, such as current location or real-time heart rate. In addition to the characteristics of the available network, the usability of the Mobile Host depends on computational resources of the device itself. Currently, some emerging lightweight frameworks to host web services on mobile devices have been developed. They are recognized for their low resources footprint but they are barely tested. Consequently, the potential of utilizing them in real life settings is not known yet. In this paper, we address this issue and we propose to test the performance of Web Services hosted on mobile devices. We first propose an architecture that allows the deployment of Web Services on mobile devices. The architecture implements an important feature that provides the possibility of resuming and managing the connection state when disconnections happen. Then, we identify and evaluate the QoS of these web services such as response time, availability, throughput, and scalability. We also evaluate the overall performance of the mobile device host with main focus on the battery consumption. We applied our experiments to both SOAP and RESTful Web Services. The results we have obtained are promising and confirm the fact that RESTful Web Services are more convenient for mobile devices as their QoS does not degrade considerably and is kept at a satisfactory level. It also proves the potential hosting of Web Services on current mobile devices with acceptable battery consumption.