How to Install / Upgrade: RSPack 2.0: Performance Gains, Leaner Dependencies and ESM Core

Rspack 2.0 from ByteDance brings a pure ESM core, leaner dependencies, improved static analysis, and RSC support, along with large build-time gains in performance benchmarks. The release centers on modern ECMAScript modules and a smaller dependency surface while the project continues to grow on npm.

To install or upgrade, move your project to Rspack 2.0 through your package manager and resolve any packages that still expect a non-ESM or heavier dependency graph. Prefer ESM entry points and config so the pure ESM core can load cleanly, then reinstall dependencies so the reduced set from 2.0 is what your lockfile actually uses. After install, run a full production build and a development build so you can compare wall-clock time and output against your previous Rspack setup.

Gotchas center on ESM and RSC: tools or plugins that assume CommonJS-only loading may fail against the pure ESM core, and RSC-related code paths need an environment that actually supports that model. Verify by confirming the installed package is 2.0, that the build completes without module-format errors, that static analysis does not surface unexpected broken imports, and that RSC-related routes or components still compile and run if you use them. Treat a clean install, a successful build, and stable app behavior under the new core as the upgrade checklist.