> How many Matrix servers are out there ? One, that is still in beta (Synapse). Worth noting that Matrix as a protocol and Synapse as a server implementation left beta in June 2019 (https://matrix.org/blog/2019/06/11/introducing-matrix-1-0-an...). Matrix is deployed by governments and civic institutions the world over including emergency services. It is literally trusted in life or death situations.

While Synapse is the most mature server implementation there are others under active development listed here - https://matrix.org/docs/projects/try-matrix-now.