This document discusses the relationship between circular economy practices and open source technologies. It argues that open source technologies have become good enough in the last decade to support circular design approaches. Examples provided include how the Open Compute Project (OCP) uses open source designs and principles of modularity and disaggregation to dramatically reduce materials usage in data centers through approaches like tool-less server assembly. The document advocates that open source technologies and collaborative design can help achieve greater levels of reuse and recycling in line with circular economy goals.