# @web/dev-server-polyfill

> Dev server plugin for loading polyfills

Latest version **2.0.0** (published 2026-07-07) · MIT license · 0 weekly downloads

## Install

```sh
npm install @web/dev-server-polyfill
pnpm add @web/dev-server-polyfill
yarn add @web/dev-server-polyfill
bun add @web/dev-server-polyfill
```

## Health

**Score 70/100 (B)** — status: active.

Positive: has types; esm support; no vulnerabilities; has provenance; recently updated; high maintenance score.

Warnings: low downloads.

## Facts

| | |
|---|---|
| Version | 2.0.0 |
| Published | 2026-07-07 |
| First published | 2023-10-25 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | bundled |
| Module format | ESM |
| Node | >=22.0.0 |
| Dependencies | 2 |
| Unpacked size | 5.3 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Provenance | attested (GitHub Actions) |
| GitHub stars | 2451 |
| Author | modern-web |
| Maintainers | d4kmor, passle, jorenbroekema, bennyp, larsdenbakker, westbrook, modern-web |
| Keywords | web, polyfill |

## Links

- npm: https://www.npmjs.com/package/@web/dev-server-polyfill
- Repository: https://github.com/modernweb-dev/web
- Homepage: https://github.com/modernweb-dev/web/tree/master/packages/dev-server-polyfill
- Issues: https://github.com/modernweb-dev/web/issues
- npm.io page: https://npm.io/package/@web/dev-server-polyfill

## Dependencies (2)

- [@web/dev-server](https://npm.io/package/@web/dev-server.md) ^1.0.0
- [@web/polyfills-loader](https://npm.io/package/@web/polyfills-loader.md) ^3.0.0

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## Recent versions

- 2.0.0 (latest) — 2026-07-07
- 0.0.0-canary-20240219104536 (canary) — 2024-02-19
- 1.0.6 — 2025-02-28
- 1.0.5 — 2025-02-27
- 0.0.0-canary-20240219104126 — 2024-02-19
- 0.0.0-canary-20240212171943 — 2024-02-12
- 0.0.0-canary-20240105101412 — 2024-01-05
- 0.0.0-canary-20240105095248 — 2024-01-05
- 0.0.0-canary-20240105093823 — 2024-01-05
- 0.0.0-canary-20240105092607 — 2024-01-05
- 0.0.0-canary-20240105091725 — 2024-01-05
- 0.0.0-canary-20231122093600 — 2023-11-22
- 1.0.4 — 2023-11-01
- 1.0.3 — 2023-10-26
- 1.0.2 — 2023-10-25
- … 1 more at https://npm.io/package/@web/dev-server-polyfill/versions

## README

# Dev server polyfill

Plugin to load polyfills during development. Uses [`@web/polyfills-loader`](https://modern-web.dev/docs/building/polyfills-loader/) internally.

## Usage

`web-dev-server.config.js`:

```js
import { polyfill } from '@web/dev-server-polyfill';

export default {
  plugins: [
    polyfill({
      scopedCustomElementRegistry: true,
    }),
  ],
};
```

You can find the supported polyfills [here](https://modern-web.dev/docs/building/polyfills-loader/#polyfills).

You can also provide custom polyfills:

`web-dev-server.config.js`:

```js
import { polyfill } from '@web/dev-server-polyfill';

export default {
  plugins: [
    polyfill({
      custom: [
        {
          name: 'my-feature-polyfill',
          path: 'path/to/my/polyfill.js',
          test: "!('myFeature' in window)",
        },
      ],
    }),
  ],
};
```

You can find the configuration options for providing custom polyfills [here](https://modern-web.dev/docs/building/polyfills-loader/#custom-polyfills).

---
_Source: https://npm.io/package/@web/dev-server-polyfill · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._