ByteDance releases Rspack 2.0: Improves performance by another 10% compared to version 1.7.

On April 24th, ByteDance officially released Rspack 2.0. Compared to version 1.0, version 2.0 has achieved comprehensive improvements in performance, API design, and product form: not only has the overall build performance improved by about 10% compared to version 1.7 (can be improved by up to 100% compared to version 1.0), the default npm dependencies have been greatly reduced, ESM support has been improved, static analysis capabilities have been enhanced, and new features such as React Server Components have been experimentally introduced. Looking back at the 1.x phase, the stage goal of "achieving 10 times improvement in build performance while maintaining compatibility with webpack API and ecosystem" has been basically achieved. Rspack not only implements webpack's core capabilities and plugin API, but continues to evolve in development experience, product optimization, and support for modern language features, gradually introducing and improving new features such as incremental build, on-demand compilation, persistent caching, constant inlining, virtual modules, Barrel file optimization, and more. At the same time, Rspack is increasingly being adopted by more and more users. Compared to when version 1.0 was released, Rspack's weekly download volume has grown from 100,000 to 5 million. Starting from version 2.0, while maintaining compatibility with the webpack ecosystem, Rspack will gradually introduce default behaviors, API design, and build products that are more in line with modern JavaScript development. This will be a gradual process, and the company will try to avoid introducing too many incompatible changes in a single major version, while also providing migration guides and Agent Skills to keep migration costs within an acceptable range. This version 2.0 brings a series of major updates: in terms of performance improvement, compared to Rspack 1.7, Rspack 2.0's overall performance has improved by about 10%, with a maximum improvement of 100% compared to version 1.0. In scenarios where persistent caching is enabled, build performance and memory usage have been further improved. Now Rspack supports caching and reusing the results of the SWC compression plugin, with a performance improvement of about 50% when the cache is hit. By optimizing the underlying storage implementation, memory usage has decreased by over 20% when caching is enabled. Additionally, Rspack 2.0 has reduced the number of default npm dependencies, with the dependency count of @rspack/dev-server reduced from 192 to 1, reducing the installation volume by over 90%; @rspack/cli has even achieved zero dependencies. On the product optimization level, Rspack 2.0 significantly enhances static analysis capabilities, enabling more complex code patterns to be included in Tree Shaking optimization. Rspack 2.0 also introduces compiler annotation support, allowing developers to mark functions as side-effect-free using #__NO_SIDE_EFFECTS__. In addition, Rspack 2.0 now supports Tree Shaking of shared dependencies in module federation, allowing shared dependencies to be pruned at the export level, removing unused parts to reduce the size of shared packages. In improving ESM support, Rspack's core package is now released in the form of a pure ESM package, removing its own CommonJS build products, making module loading more consistent and more in line with current Node.js best practices. Rspack 2.0 also improves support for import.meta and import.defer. In terms of new features, Rspack 2.0 also provides experimental low-level build support for React Server Components (RSC), including directive support, compile-time checks, CSS support, and HMR support. ByteDance is also collaborating with the TanStack team to plan support for RSC in TanStack Start and TanStack in future versions. Additionally, Rspack 2.0 supports subpath alias imports in the #/ form, simplifying swc-loader configuration, supporting control over CSS imports, using hashes as module IDs, and more. ByteDance stated that in the future, it will continue to advance the evolution of Rspack from multiple directions, including product optimization, Agent support, and toolchain coordination. In terms of product optimization, Rspack's goal is not only to build faster, but also to generate higher-quality products while ensuring stable behavior. The company will continue to improve tree shaking, code splitting, and static analysis capabilities, explore optimization analysis combined with static type information, and provide finer-grained code splitting and optimization options. As Coding Agent gradually becomes an important user of development tools, ByteDance will also consider these scenarios more in the design, making it easier for Agents to understand and handle build issues. For example, by providing Agents with richer debugging information, performance data, and other context through CLI, helping them more accurately analyze and participate in issue troubleshooting and performance optimization. In terms of toolchain coordination, in actual projects, time is often consumed not only by packaging itself, but also by testing, type checking, and code checking, which also bring significant overhead. ByteDance will continue to promote the coordinated evolution of the Rstack toolchain and integrate it with typescript-go. For example, Rslint now supports rslint --type-check, which can perform both code checking and type checking simultaneously. In the future, the company will also support typescript-go in the ts-checker-rspack-plugin.