Yelp's engineering team migrated their JavaScript monorepo from Webpack to Rspack, achieving approximately 52% reduction in build times. Key reasons for choosing Rspack included its strong Webpack compatibility, which minimized migration friction. The team used an adapter pattern to preserve existing Webpack configs while making targeted replacements, and rolled out the change gradually via opt-in per page. Additional optimizations included converting star re-exports and import-then-export patterns to true re-exports using codemods, and enabling Rspack's portable persistent cache (which yielded up to 80% reduction on warm cache builds). Storybook integration was handled via storybook-react-rsbuild, with Rsbuild defaults ejected to avoid plugin duplication. Future plans include replacing Babel with the Rust-based SWC transpiler for further gains.
