As web technology and (big) data continue to transform how we organize ourselves, scholarly research increasingly zooms in on the socio-material conditions of citizen participation and public engagement, the objects and devices that organize publics. Where social issues may often be the driver of such public engagement, increasingly the city and, more specifically, the neighborhood itself have become a central objects connecting their inhabitants through online networks and neighborhood events. Tools and apps for citizen participation then weave together neighborhood stakeholders (e.g. inhabitants, municipal parties and entrepreneurs). This paper zooms in on a sample of 40 such tools that enable and organize bottom-up citizen participation in the city of Amsterdam. Combining a theoretical framework with content analysis, digital methods and data visualization, this paper marks the starting point of a longitudinal analysis of online tools for the urban bottom-up movement.