From their intro [0]:
We created Rspack to solve various performance problems we encountered while maintaining building tools at ByteDance. There were no tools in the market that could solve these problems well. We have a large number of monolithic applications within the company, all of which have very complex webpack configurations.<p>This makes rspack looks like a competitor to Turbopack which is marketed as webpack's successor.<p>[0] <a href="https://www.rspack.dev/guide/introduction.html" rel="nofollow">https://www.rspack.dev/guide/introduction.html</a>
I wonder how this compares (performance and feature-wise) to esbuild (<a href="https://github.com/evanw/esbuild">https://github.com/evanw/esbuild</a>), which is also a bundler written in a compiled language (Go)? esbuild claims to be 10-100x faster than JS-based builders, while Rspack doesn't provide any concrete numbers (at least I didn't find any)...
If I were the author, I would consider renaming this, as "spack" (from the etymology "spastic" -> "spacker") is an offensive term for someone with cerebral palsy, in British English.