The quickly growing demand for wireless networks and the numerous application-specific requirements stand in stark contrast to today's inflexible management and operation of wireless networks. While most research focuses on mobile networks, WiFi is often left out of the purview. In this paper, we present and evaluate OpenSDWN, a novel WiFi architecture based on a joint software-defined network and network functions virtualization approach. OpenSDWN exploits virtualization across the wired and wireless network and introduces datapath programmability to enable service differentiation and fine-grained transmission control, facilitating the prioritization of critical applications. OpenSDWN implements per-client virtual access points and per-client virtual middleboxes, to render network functions more flexible and support mobility and seamless migration. Moreover, OpenSDWN also increases the security of upcoming WiFi HotSpot architectures by following a functional split approach. Finally, OpenSDWN can also be used to out-source the control over the home network to a participatory interface or to an Internet service provider.