# What changed in @rsbuild/core

> 106 changes in @rsbuild/core 1 to 2 from its official release notes, upgrade guides and advisories: 88 breaking, 4 deprecations, 7 new APIs and options. Each one cited. Sources checked 2026-10-18. HTML: https://unstale.sh/npm/@rsbuild/core/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## @rsbuild/core 2

### Breaking changes

- The webpack type has been removed from api.context.bundlerType. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The webpack chain plugin hook has been removed. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The webpack config plugin hook has been removed. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- This plugin hook replaces api.onAfterStartProdServer. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- This plugin hook replaces api.onBeforeStartProdServer. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The built-in CSS rule now has a oneOf branch for normal CSS transforms; custom loaders on CHAIN_ID.RULE.CSS should move here. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The deprecated template parameters have been removed. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- Use htmlPlugin instead of htmlWebpackPlugin. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The query parameter is removed; use ?url instead. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The loader parameter now defaults to auto instead of jiti, preferring the native Node.js loader. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- Instance loggers are no longer affected by the global logger.override(); customized Rsbuild logs should switch to customLogger. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- Projects using Module Federation v1.5 through moduleFederation.options must install this optional peer dependency manually. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The default Node.js target changes from Node 16 to Node 20+. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- Rsbuild 2.0 requires Node.js 20.19+ or 22.12+; Node.js 18 is no longer supported. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- With output.target set to node, output.module now defaults to ESM; projects must load ESM bundles or opt back into CommonJS. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The option is removed; use Rsdoctor or register webpack-bundle-analyzer yourself through tools.rspack. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The option is removed; use stats.toJson() in a custom plugin to emit a stats JSON file. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The option is removed because Rspack v2 does not include Moment locales by default. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The provider configuration option has been removed. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The package is now published as pure ESM, affecting how projects load it. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The deprecated compiler parameter has been removed. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- This method replaces rsbuild.onAfterStartProdServer. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- This method replaces rsbuild.onBeforeStartProdServer. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The deprecated compiler parameter has been removed. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The default host changes from 0.0.0.0 to localhost, preventing network exposure by default. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- In array-style proxy config, changeOrigin now defaults to true, matching record-style config. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The proxy context option is replaced by pathFilter. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- Proxy events are configured together through the on option instead of separate onOpen, onClose, onError, onProxyReq, and onProxyRes options. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The deprecated content-changed message type has been removed; use full-reload instead. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The deprecated option is removed; use resolve.alias instead. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The deprecated option is removed; use resolve.aliasStrategy instead. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The default decorators version changes from 2022-03 to 2023-11. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The webpack tools configuration option has been removed. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The webpackChain tools configuration option has been removed. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The default web browserslist now targets the Baseline Widely Available query from 2025-05-01, changing JavaScript and CSS transformations and polyfill behavior. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- Rsbuild 2.0 no longer supports webpack as a bundler. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- Use rspackConfig instead of webpackConfig. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)

### Deprecations

- The option is deprecated; use server.setup instead. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The option still works but is deprecated; migrate to splitChunks. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)

### New APIs and options

- The flag enables network access on demand by using the host option. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The new option replaces performance.chunkSplit and aligns with Rspack optimization.splitChunks, including presets for common strategies. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)

### Behavior and default changes

- The built-in CSS rule now has a oneOf branch for ?inline imports. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The built-in CSS rule now has a oneOf branch for ?raw imports. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The built-in JavaScript rule now has a oneOf branch for SWC transforms; custom loaders previously added to CHAIN_ID.RULE.JS should move here. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- The built-in JavaScript rule now has a oneOf branch for ?raw imports. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- With output.target set to node, minification remains disabled by default, preserving clearer stack traces for debugging. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)
- style-loader is upgraded from v3 to v4, and some tools.styleLoader options have changed. (2.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v1-to-v2)

## @rsbuild/core 1

### Breaking changes

- This API has been removed and replaced with environment.entry. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This API was removed and replaced with environment.entry. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This API has been removed and replaced with environment.target. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This API was removed and replaced with environment.target. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This API has been removed and replaced with environment.htmlPaths. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This API was removed and replaced with environment.htmlPaths. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- The default changed from <port> to an empty string, which uses location.port. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The default changed from '<port>' to '' so the client uses location.port; set '<port>' to preserve the previous behavior. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This configuration key has been renamed to server.open. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This option was renamed to server.open. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- Replaces api.context.entry for accessing an environment's entry. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This environment property replaces api.context.entry. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- Replaces api.getHtmlPaths for accessing HTML paths on an environment. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This environment property replaces api.getHtmlPaths. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- Replaces api.context.targets for accessing an environment's target. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This environment property replaces api.context.targets. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- HTML files are no longer minified by Rsbuild; a standalone plugin is available to support HTML minification. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- Rsbuild no longer minifies HTML files; a standalone plugin is available to support HTML minification. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- The option now supports generating web app manifests, and its type has changed to an object containing icons. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The option now supports generating web app manifests, and its type has changed from a path string to an object containing icons. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- Rsbuild now enables lightningcss-loader by default to transform CSS files, replacing autoprefixer for vendor prefixes and improving performance. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- Rsbuild now enables lightningcss-loader by default to transform CSS files, replacing autoprefixer for vendor prefixes and improving performance. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- The hook can now be triggered multiple times in watch mode. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The hook can now trigger multiple times in watch mode. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- The default changed from ascii to utf8; configure ascii to retain the previous behavior. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The default charset changed from 'ascii' to 'utf8'; configure 'ascii' to retain the previous behavior. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This option has been removed; configure the server environment's output.distPath.root instead. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The option is now boolean rather than accepting a target-dependent function; use environments configuration for differing behavior. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The option now has boolean type; use environments to configure it differently for each target. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This option has been removed, and Rsbuild no longer minifies HTML files; use the standalone plugin to enable HTML minification. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This option has been removed, and Rsbuild no longer minifies HTML files by default; use the standalone plugin for HTML minification. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This option has been removed; use the standalone plugin to enable HTML minification. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This option has been removed; use the standalone HTML minifier plugin if HTML minification is needed. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- The option no longer supports a Record<RsbuildTarget, string[]> value; use environments configuration instead. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The option no longer supports the Record<RsbuildTarget, string[]> type; configure values per environment instead. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- The default is now 'off', reducing polyfill code and bundle size; set it to 'usage' or 'entry' if the application needs polyfills. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This option has been removed; configure output.target and environments for multi-environment builds. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This option has been removed; use output.target and environments for multi-environment configuration. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- Replaces rsbuildServer.onHTTPUpgrade for the dev server API. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This API replaces rsbuildServer.onHTTPUpgrade. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This API has been removed and replaced with rsbuildServer.connectWebSocket. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This API was removed and replaced with rsbuildServer.connectWebSocket. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This is the replacement configuration key for dev.startUrl. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The target parameter was removed from the source.alias function; use environments configuration instead. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The target parameter was removed from the source.alias function; configure aliases per environment instead. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- The default decorators version is now 2022-11; configure version: 'legacy' to retain legacy decorators. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The default decorators version is now '2022-11'; configure version: 'legacy' for legacy decorators. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- Function usage of source.entry has been removed; use environments configuration instead. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- Function usage of source.entry was removed; configure entries per environment instead. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This configuration option has been removed; autoprefixer can still be enabled through a PostCSS config file. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- This configuration option has been removed; autoprefixer can still be enabled through a PostCSS config file. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)

### Deprecations

- The plugin is deprecated and no longer needed because lightningcss-loader is enabled by default. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- The plugin is deprecated and no longer needed because Rsbuild enables lightningcss-loader by default. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)

### New APIs and options

- A new hook is triggered after executing the build of a single environment. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- A new hook is triggered after executing the build of a single environment. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- A new hook is triggered before executing the build of a single environment. (1.0.0) — [upgrade guide](https://rsbuild.rs/guide/upgrade/v0-to-v1)
- A new hook is triggered before executing the build of a single environment. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)
- This option replaces dev.startUrl for configuring whether to open the server. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)

### Behavior and default changes

- The default is now 'off', reducing polyfill code and bundle size; set it to 'usage' or 'entry' if the application needs polyfills. (1.0.0) — [upgrade guide](https://v1.rsbuild.rs/guide/upgrade/v0-to-v1)