Domain-specific languages (DSLs) are languages tailored for particular domains. Many frameworks and tools have been proposed to develop editors for DSLs, especially for desktop IDEs, like Eclipse. We are witnessing the advent of low-code development platforms, which are cloud-based environments supporting rapid application development by using graphical languages and forms. While this approach is very promising, the creation of new low-code platforms may require the migration of existing desktop-based editors to the web. However, this is a technically challenging task. To fill this gap, we present ROCCO, a tool that migrates Eclipse-based graphical modelling editors to the web, to facilitate their integration with low-code platforms. The tool reads a meta-model annotated with EuGENia annotations, and generates a web editor using the DPG web framework used by the UGROUND company. In this paper, we present the approach, including tool support and an evaluation based on migrating nine editors created by third parties, which shows the usefulness of the tool.