A functional prototype of a smartphone web app is developed to promote oil spill information exchange with citizens. Based on a client-server system design, the prototype is developed on open source platform by integrating state-of-art geographic information technologies, like HTML5, PostGIS, jQuery and Leaflet. The prototype enables user reporting of oil spill observation as well as capturing of image and geolocation. Use cases and user stories together with personas are used for system design and interactive testing. The agile framework Scrum is applied as development methodology. Opportunities and challenges regarding both technologies and organizational issues are discussed during the development. The major contribution of this project is the demonstration of the potential of smartphone PPGIS for information exchange and citizen’s reports as decision support for authorities during large oil spill clean-up operations.