#Performance

performance configures Rspack's performance hint mechanism, helping you identify oversized outputs during the build.

It compares asset sizes and entrypoint total sizes against thresholds to decide whether hints should be emitted, and hints controls the hint level (warning / error / disabled).

You can define budget thresholds with maxAssetSize and maxEntrypointSize, and use assetFilter to exclude files that should not be counted, so hints better match your real performance goals.

#performance

• Type: false | object

Set performance to false to disable the performance hints:

export default {
  performance: false,
};

#performance.assetFilter

• Type: (assetFilename: string) => boolean

Used to filter which assets are included in performance hint calculations. Files returning true are included, and files returning false are ignored.

Ignore CSS files when calculating performance hints:

export default {
  performance: {
    assetFilter: (assetFilename) => !assetFilename.endsWith('.css'),
  },
};

#performance.hints

• Type: false | 'error' | 'warning'
• Default:production mode iswarning, development mode isfalse

Controls whether performance hints are enabled and which level to use:

• false: Disable performance hints
• 'warning': Emit hints as warnings
• 'error': Emit hints as errors, which fails the build

Treat performance hints as build errors:

export default {
  performance: {
    hints: process.env.NODE_ENV === 'production' ? 'error' : false,
  },
};

#performance.maxAssetSize

• Type: number
• Default:250000

Sets the size threshold for a single asset (in bytes). Rspack emits a performance hint when an asset exceeds this value.

Lower the single asset size limit to catch oversized files earlier:

export default {
  performance: {
    maxAssetSize: 100000,
  },
};

#performance.maxEntrypointSize

• Type: number
• Default:250000

Sets the total size threshold for an entrypoint (in bytes). Entrypoint total size means the total size needed for the initial load of that entry. Rspack emits a performance hint when the entrypoint total size exceeds this value.

For example, set the entrypoint size threshold to 500 KB:

export default {
  performance: {
    maxEntrypointSize: 500000,
  },
};