In modern model-based development collaboration comes in two levels. First, developers want to create, edit and check the same shared specifications and avoid handling conflicts, run diff and merge activities etc. all taking time from the actual development work. Second, also language developers defining modeling languages, generators, notations, checks etc. want to collaborate similarly too. Slides describe how to work collaboratively in MetaEdit+ tool with models and metamodelsand as well as describe the benefits it provides.