The complexity of urban innovation needs adaptive and dynamic tools for organisations, governments and citizens to be able to test and experiment at different scales - neighborhoods, districts, city scale, peri-urban scale, etc. In a constantly changing reality, we also need tools that are able to adapt and that can provide updated and validated information and resources, in an open source fashion. As such, this Handbook provides both REFLOW’s pilot cities and other interested cities with access to an updated repository of tools, methods and metrics, to embrace the transition towards a more circular and regenerative urban model.