Аннотация:This paper discusses the city-scale context-aware mobile information system and programming interfaces - CityProximus. Our project is based on the ideas of network proximity. De-facto, network related information is the easiest way for getting context-related information on mobile devices. It lets us replace geo-information in location based services with data about available networks and network nodes. So, in the proposed system user-defined information could be directly associated with existing and specially created network nodes. Later, this information could be delivered to mobile users being in the proximity to the above-mentioned network nodes. In this paper, we discuss the technical aspects of implementation for such system on the city level.