OCK is a mobile application that enables inhabitants to share their experiences in the city, it’ buildings, parks etc. on a collaborative knowledge platform. Smart cities make use of data from sensors to enhance efficiency of urban services.  Open City Knowledge (OCK) enables this data to be enriched with human experiences and artificial intelligence. This knowledge can come from the city’s inhabitants, planners, emergency services, etc. This makes feedback instantaneous and easy, enabling quick responses and efficient planning, maintenance, etc. from city services.