The Welikeia project and the corresponding free online tool Visionmaker. NYC focus on the historical landscape ecologies of New York City. This article provides a brief introduction to online participatory tools, describes the Visionmaker tool in detail, and offers suggested ways to use the tool for Extension professionals based in and outside New York City. This information provides a basis for best practices Extension professionals can apply when using Visionmaker to support ecological thinking and participatory planning to catalyze change among urban residents.