Ensuring the sustainability of Open Source projects is important, especially when organized in ecosystems of interrelated projects. Generic methodologies like SQALE or QualOSS describe how to assess maturity covering product, process and community aspects. Specific ecosystems have defined their own quality model, like OW2’s SQUaT Mature Transition Checklist. Such quality assessment of Open Source Ecosystems should be efficiently supported. In this talk we will present the CHOOSE toolset we have developed to help in automating and uniformly managing the quality of a whole Open Source Ecosystems. Our toolset is based on 35 key indicators related to maintainability, reliability and community which are used to implement and automate the production of OW2’s Mature Transition Checklist. The generic architecture of the toolset will be presented how it is instantiated to implement the OW2 Mature Transition Checklist and to efficiently interface with the OW2 forge. The toolset implementation will also be detailed stressing the use of Open Source components for the workflows’ orchestration (Bonita), project/code analysis tools (HtmlUnit, QualOSS) and automatic report generation tools (JasperReports). Finally, a validation on a subset of 21 OW2 projects with an in-depth focus on a few projects (Chameleon, Spago and Orchestra) to produce maturity reports.