Matrix/Server
Matrixis a protocol, it needed a server to be used.
As of 2023 there is no production ready matrix server: the only working server implementation is Synapse, a prototype server written in Python scripting language using lot of resources.
See /What v1.0 means to me as something a server operator (who offers public services) expect from a prod ready server.
The Servers in development
There are some projects planning to create a real server, but none of them are ready. In order of completeness:
The Construct
It is written in C++, based on compressed RocksDB as a storage backend, by a single independent developer.
The server has a working private version, lacking some features required for public use.
The developer (Jason) is actively blocked from the specification process by Element, Inc., also they deliberately ignore reports about Synapse protocol incompatible behaviour causing problems in the development. This also results no coordination of protocol development with the developer which makes the protocol as a moving target for implementation, which severely hinders development.
Dendrite
Dendrite is organised by Element, Inc. (the principal developer left around november 2022, and now a team seem to develop it); it is written in goloang.
The server has a partial implementation of the Matrix protocol, and some working private test servers exist.
Conduit
It is written in Rust (building on Ruma matrix framework) by one independent developer, and uses a RocksDB backend.
The server has a partial implementation of the Matrix protocol, and some working private test servers exist.