There are several open source registry server projects, which can be used to self-host a private registry server.
Meuse is an open source Rust registry server written in Clojure.
Shipyard.rs uses Meuse underneath the hood. It has proven to be a solid piece of code over time, in our estimation.
Potential downsides include the source code language, Clojure, which may not be familiar to Rust developers, as well as fairly expensive memory usage of JVM-based programs.
Other projects, which we are aware of but do not have extensive experience using, include:
- gitlab-cargo-shim: bare-bones, git-based registry server without Cargo compatibility
See also: rust-lang list of open source registry servers