# speed-measure-webpack-plugin
> Measure + analyse the speed of your webpack loaders and plugins
Latest version **1.6.0** (published 2026-03-24) · MIT license · 0 weekly downloads
## Install
```sh
npm install speed-measure-webpack-plugin
pnpm add speed-measure-webpack-plugin
yarn add speed-measure-webpack-plugin
bun add speed-measure-webpack-plugin
```
## Health
**Score 53/100 (C)** — status: active.
Positive: has types package; no vulnerabilities; high quality score.
Warnings: low downloads; no esm support.
## Facts
| | |
|---|---|
| Version | 1.6.0 |
| Published | 2026-03-24 |
| First published | 2018-01-29 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | separate (@types/speed-measure-webpack-plugin) |
| Module format | CommonJS |
| Node | >=6.0.0 |
| Dependencies | 1 |
| Unpacked size | 360 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 2441 |
| Author | Stephen Cook |
| Maintainers | stephencookdev |
## Links
- npm: https://www.npmjs.com/package/speed-measure-webpack-plugin
- Repository: https://github.com/stephencookdev/speed-measure-webpack-plugin
- Homepage: https://github.com/stephencookdev/speed-measure-webpack-plugin#readme
- Issues: https://github.com/stephencookdev/speed-measure-webpack-plugin/issues
- npm.io page: https://npm.io/package/speed-measure-webpack-plugin
## Dependencies (1)
- [chalk](https://npm.io/package/chalk.md) ^4.1.0
## Recent versions
- 1.6.0 (latest) — 2026-03-24
- 1.0.0-beta-1 (beta) — 2018-02-20
- 1.5.0 — 2021-03-28
- 1.4.2 — 2021-01-23
- 1.4.1 — 2021-01-23
- 1.4.0 — 2021-01-23
- 1.3.3 — 2020-03-23
- 1.3.2 — 2020-03-22
- 1.3.1 — 2019-03-19
- 1.3.0 — 2019-01-19
- 1.2.5 — 2018-12-27
- 1.2.3 — 2018-09-24
- 1.2.2 — 2018-04-06
- 1.2.1 — 2018-04-06
- 1.2.0 — 2018-03-27
- … 20 more at https://npm.io/package/speed-measure-webpack-plugin/versions
## README
The first step to optimising your webpack build speed, is to know where to focus your attention.
This plugin measures your webpack build speed, giving an output like this:
## Install
```bash
npm install --save-dev speed-measure-webpack-plugin
```
or
```bash
yarn add -D speed-measure-webpack-plugin
```
## Requirements
SMP requires at least **Node v6**. But otherwise, accepts **all webpack** versions (1, 2, 3, 4, and 5).
To work on the repository itself and run the test suite, use **Node v18+**.
## Usage
Change your webpack config from
```javascript
const webpackConfig = {
plugins: [new MyPlugin(), new MyOtherPlugin()],
};
```
to
```javascript
const SpeedMeasurePlugin = require("speed-measure-webpack-plugin");
const smp = new SpeedMeasurePlugin();
const webpackConfig = smp.wrap({
plugins: [new MyPlugin(), new MyOtherPlugin()],
});
```
and you're done! SMP will now be printing timing output to the console by default.
Check out the [examples folder](/examples) for some more examples.
## Options
Pass these into the constructor, as an object:
```javascript
const smp = new SpeedMeasurePlugin(options);
```
### `options.disable`
Type: `Boolean`
Default: `false`
If truthy, this plugin does nothing at all.
`{ disable: !process.env.MEASURE }` allows opt-in measurements with `MEASURE=true npm run build`.
### `options.outputFormat`
Type: `String|Function`
Default: `"human"`
Determines in what format this plugin prints its measurements
- `"json"` - produces a JSON blob
- `"human"` - produces a human readable output
- `"humanVerbose"` - produces a more verbose version of the human readable output
- If a function, it will call the function with the JSON blob, and output the response
### `options.outputTarget`
Type: `String|Function`
Default: `console.log`
- If a string, it specifies the path to a file to output to.
- If a function, it will call the function with the output as the first parameter
### `options.pluginNames`
Type: `Object`
Default: `{}`
By default, SMP derives plugin names through `plugin.constructor.name`. For some
plugins this doesn't work (or you may want to override this default). This option
takes an object of `pluginName: PluginConstructor`, e.g.
```javascript
const uglify = new UglifyJSPlugin();
const smp = new SpeedMeasurePlugin({
pluginNames: {
customUglifyName: uglify,
},
});
const webpackConfig = smp.wrap({
plugins: [uglify],
});
```
### `options.excludedPlugins`
Type: `Array`
Default: `[]`
Excludes plugins from SMP's proxy wrapping. Entries can be:
- a plugin name
- a plugin constructor
- a regular expression matched against plugin names
Name matching checks both `options.pluginNames` aliases and constructor names. E.g.
```javascript
const smp = new SpeedMeasurePlugin({
pluginNames: {
customReactRefresh: reactRefreshPlugin,
},
excludedPlugins: [
"customReactRefresh",
MiniCssExtractPlugin,
/SomeLegacyPlugin$/,
],
});
```
### `options.loaderTopFiles`
Type: `Number`
Default: `0`
You can configure SMP to include the files that take the most time per loader, when using `outputFormat: 'humanVerbose'`. E.g., to show the top 10 files per loader:
```javascript
const smp = new SpeedMeasurePlugin({
outputFormat: "humanVerbose",
loaderTopFiles: 10,
});
```
### `options.compareLoadersBuild`
Type: `Object`
Default: `{}`
This option gives you a comparison over time of the module count and time spent, per loader. This option provides more data when `outputFormat: "humanVerbose"`.
Given a required `filePath` to store the build information, this option allows you to compare differences to your codebase over time. E.g.
```javascript
const smp = new SpeedMeasurePlugin({
compareLoadersBuild: {
filePath: "./buildInfo.json",
},
});
```
### `options.granularLoaderData` _(experimental)_
Type: `Boolean`
Default: `false`
By default, SMP measures loaders in groups. If truthy, this plugin will give per-loader timing information.
This flag is _experimental_. Some loaders will have inaccurate results:
- loaders using separate processes (e.g. `thread-loader`)
- loaders emitting file output (e.g. `file-loader`)
We will find solutions to these issues before removing the _(experimental)_ flag on this option.
### `options.excludedLoaders`
Type: `Array`
Default: `[]`
When you enable `granularLoaderData`, SMP prepends its timing loader to each matching
loader rule. Use this option to skip rules whose loader chain contains a matching
loader name or regular expression. String matching checks both the original loader
request and the normalized package name. E.g.
```javascript
const smp = new SpeedMeasurePlugin({
granularLoaderData: true,
excludedLoaders: ["thread-loader", /mini-css-extract-plugin/],
});
```
## FAQ
### What does general output time mean?
This tends to be down to webpack reading in from the file-system, but in general it's anything outside of what SMP can actually measure.
### What does modules without loaders mean?
It means vanilla JS files, which webpack can handle out of the box.
## Contributing
Contributors are welcome! 😊
Please check out the [CONTRIBUTING.md](./CONTRIBUTING.md).
## Migrating
SMP follows [semver](https://semver.org/). If upgrading a major version, you can consult [the migration guide](./migration.md).
## License
[MIT](/LICENSE)
## Contributors ✨
Thanks goes to these wonderful people ([emoji key](https://allcontributors.org/docs/en/emoji-key)):
This project follows the [all-contributors](https://github.com/all-contributors/all-contributors) specification. Contributions of any kind welcome!
---
_Source: https://npm.io/package/speed-measure-webpack-plugin · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._
