This article explores the potential of web-based participatory mapping tools for urban planning purposes and spatial information creation in informal settlements, i.e. the slums (barrios) of Caracas, Venezuela. While an increasing use of mapping tools is found in developed countries, fewer applications are found in informal settlements of developing countries, due to issues of high informality, illegality, and a lack of information, human and financial resources. In the context of course-based mapping activities directed to neighbourhood Sector-level planning officers and action research, this study has employed a two-tier approach (planning officials doing the mapping and eliciting complementary information from the population) to online participatory mapping (Google My Maps) for urban planning purposes in the barrios of Caracas. Our efforts aimed mostly at identifying and mapping public facilities, and planned and under-construction public works. This research aims to show the potential contribution of such tools to planning informal settlements and creating locally-produced spatial information. The outcomes of the mapping courses have already proven to be useful for planning public projects across Sectors and Communes, mutual consideration of their priorities in the preparation of two-year development plans, and for increased awareness of local residents of communal councils.