The Architecture, Engineering and Construction (AEC) sector has entered a new stage in the digitization of the design and construction of the built environment. Today, big companies, small startups, academic labs, are investing massively towards a brand-new paradigm in AEC :« platforms ». Traditional design software are moving from the desktop to the browser. In this context of a network-oriented environment, a new kind of flow-based workflow is emerging, combining heterogeneous design softwares. At the edge of this cultural shift, open source variant of Github such as Gitea or Forgejo, combined with the open stack of the Building Information Modeling (BIM) enable the creation of a new kind of« design forges » and new ways to conceive the act of design in a more collaborative way. We present Gitaec (gitaec.com) and Sloyd (sloyd.work) as two early example of such platforms for professionals and for education.