There is also rust-script[1] which runs "Rust files and expressions as scripts without any setup or compilation step." I wrote a data loader[2] in it for my Observable Framework project and have been very happy with its performance and overall ease including hot-reloading.<p>[1] <a href="https://rust-script.org" rel="nofollow">https://rust-script.org</a><p>[2] <a href="https://observablehq.com/framework/loaders#routing" rel="nofollow">https://observablehq.com/framework/loaders#routing</a>