I built an extensive open-source Rust-based spatial analysis platform called WhiteboxTools with the intention of serving as a plugable spatial analysis back-end for various GIS front-ends. So far people have created front ends for it in QGIS, ArcGIS, Python, and R, but I have long wanted to see people use it more in web-GIS. Perhaps one day...
https://jblindsay.github.io/ghrg/WhiteboxTools/index.html