Project Clearwater/Matrix Gateway aims to connect the open-source Project Clearwater IMS core with the decentralized Matrix communication standard by building a gateway. Project Clearwater is a massively scalable, cloud-based SIP core, while Matrix is an open standard for persistent, decentralized communication that links separate platforms but does not directly support SIP. The presentation discusses the architecture, a WebRTC demo, and SIP flows between the two systems enabled by the gateway.