Minify · Unhead

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TypeScript

- [Switch to TypeScript](https://unhead.unjs.io/docs/typescript/head/guides/plugins/minify)
- [Switch to Vue](https://unhead.unjs.io/docs/vue/head/guides/plugins/minify)
- [Switch to React](https://unhead.unjs.io/docs/react/head/guides/plugins/minify)
- [Switch to Svelte](https://unhead.unjs.io/docs/svelte/head/guides/plugins/minify)
- [Switch to Solid.js](https://unhead.unjs.io/docs/solid-js/head/guides/plugins/minify)
- [Switch to Angular](https://unhead.unjs.io/docs/angular/head/guides/plugins/minify)
- [Switch to Nuxt](https://unhead.unjs.io/docs/nuxt/head/guides/plugins/minify)

v3 (stable)

Head

- [Discord Support](https://discord.com/invite/275MBUBvgP)
- [TypeScript Playground](https://stackblitz.com/edit/github-hhxywsb5)

- Get Started
  - [Overview](https://unhead.unjs.io/docs/typescript/head/guides/get-started/overview)
  - [Introduction to Unhead](https://unhead.unjs.io/docs/typescript/head/guides/get-started/intro-to-unhead)
  - [Starter Recipes](https://unhead.unjs.io/docs/typescript/head/guides/get-started/starter-recipes)
- Core Concepts
  - [Titles & Title Templates](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/titles)
  - [Tag Sorting & Placement](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/positions)
  - [Class & Style Attributes](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/class-attr)
  - [Inline Style & Scripts](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/inner-content)
  - [Tag Deduplication](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/handling-duplicates)
  - [DOM Event Handling](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/dom-event-handling)
  - [Script Loading](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/loading-scripts)
- Build Plugins
  - [Overview](https://unhead.unjs.io/docs/typescript/head/guides/build-plugins/overview)
  - [Tree-Shaking](https://unhead.unjs.io/docs/typescript/head/guides/build-plugins/tree-shaking)
  - [useSeoMeta Transform](https://unhead.unjs.io/docs/typescript/head/guides/build-plugins/seo-meta-transform)
  - [Minify Transform](https://unhead.unjs.io/docs/typescript/head/guides/build-plugins/minify-transform)
  - [Devtools](https://unhead.unjs.io/docs/typescript/head/guides/build-plugins/devtools)
- Plugins
  - [Template Params](https://unhead.unjs.io/docs/typescript/head/guides/plugins/template-params)
  - [Alias Sorting](https://unhead.unjs.io/docs/typescript/head/guides/plugins/alias-sorting)
  - [Canonical Plugin](https://unhead.unjs.io/docs/typescript/head/guides/plugins/canonical)
  - [Infer SEO Meta](https://unhead.unjs.io/docs/typescript/head/guides/plugins/infer-seo-meta-tags)
  - [Minify](https://unhead.unjs.io/docs/typescript/head/guides/plugins/minify)
  - [Validate](https://unhead.unjs.io/docs/typescript/head/guides/plugins/validate)

Plugins

# Minify

[Copy for LLMs](https://raw.githubusercontent.com/unjs/unhead/refs/heads/main/docs/head/1.guides/plugins/minify.md)

Last updated Apr 9, 2026 by [Harlan Wilton](https://github.com/harlan-zw) in [refactor(bundler)!: named Unhead export, ctx-based transforms, dev-mode validate (#733)](https://github.com/unjs/unhead/pull/733).

On this page

- [What Does This Plugin Do?](#what-does-this-plugin-do)
- [How Do I Set Up the Plugin?](#how-do-i-set-up-the-plugin)
- [What Options Can I Configure?](#what-options-can-i-configure)
- [Build-Time Minification](#build-time-minification)
- [Standalone Minifier Utilities](#standalone-minifier-utilities)
- [Related](#related)

**Quick Answer:** The Minify plugin strips comments, collapses whitespace, and minifies inline `<script>` and `<style>` content during SSR rendering. It uses lightweight pure-JS minifiers by default — zero native dependencies, safe for edge and serverless.

## [What Does This Plugin Do?](#what-does-this-plugin-do)

The Minify plugin hooks into the SSR render pipeline and minifies:

- **Inline scripts** — strips comments, collapses whitespace, preserves string literals and ASI safety
- **Inline styles** — strips comments, collapses whitespace, removes trailing semicolons, strips leading zeros
- **JSON-LD / application/json** — re-serializes to remove pretty-printing whitespace

It automatically skips `speculationrules` and `importmap` script types, and never increases content length.

## [How Do I Set Up the Plugin?](#how-do-i-set-up-the-plugin)

Register the plugin when creating your head instance:

Input

```
import { MinifyPlugin } from 'unhead/plugins'

const head = createHead({
  plugins: [
    MinifyPlugin()
  ]
})
```

## [What Options Can I Configure?](#what-options-can-i-configure)

Input

```
export interface MinifyPluginOptions {
  /**
   * Custom JS minifier function. Set to \`false\` to disable JS minification.
   * Defaults to built-in lightweight minifier.
   */
  js?: false | ((code: string) => string)
  /**
   * Custom CSS minifier function. Set to \`false\` to disable CSS minification.
   * Defaults to built-in lightweight minifier.
   */
  css?: false | ((code: string) => string)
  /**
   * Minify JSON script types (application/ld+json, application/json).
   * @default true
   */
  json?: boolean
}
```

### [Disable Specific Minifiers](#disable-specific-minifiers)

Input

```
MinifyPlugin({
  js: false,   // skip script minification
  json: false, // skip JSON-LD minification
})
```

### [Custom Minifiers](#custom-minifiers)

Provide your own synchronous minifier function for heavier optimization:

Input

```
MinifyPlugin({
  js: (code) => myCustomJSMinify(code),
  css: (code) => myCustomCSSMinify(code),
})
```

Note: The `ssr:render` hook runs synchronously, so custom minifiers must be synchronous.

## [Build-Time Minification](#build-time-minification)

For build-time minification of static string literals inside `useHead()` / `useServerHead()` calls, enable the `minify` option on the [unified Vite plugin](https://unhead.unjs.io/docs/head/guides/build-plugins/minify-transform). This runs at build time using heavier tools (rolldown/esbuild for JS, lightningcss for CSS) that never enter your SSR runtime bundle.

vite.config.ts

```
import vue from '@vitejs/plugin-vue'
import { Unhead } from '@unhead/vue/vite'
import { createJSMinifier } from '@unhead/bundler/minify/rolldown'
import { createCSSMinifier } from '@unhead/bundler/minify/lightningcss'

export default defineConfig({
  plugins: [
    vue(),
    Unhead({
      minify: {
        js: createJSMinifier(),
        css: createCSSMinifier(),
      },
    }),
  ],
})
```

Available minifier backends:

| Package | Function | Use case |
| --- | --- | --- |
| `@unhead/bundler/minify/rolldown` | `createJSMinifier()` | JS minification (Vite 8+) |
| `@unhead/bundler/minify/esbuild` | `createJSMinifier()` | JS minification (Vite 7) |
| `@unhead/bundler/minify/lightningcss` | `createCSSMinifier()` | CSS minification |

## [Standalone Minifier Utilities](#standalone-minifier-utilities)

The built-in minifiers are also available as standalone functions for use in custom build pipelines:

Input

```
import { minifyCSS, minifyJS, minifyJSON } from 'unhead/minify'

const minifiedJS = minifyJS('// comment\nvar x = 1;')
const minifiedCSS = minifyCSS('body { margin: 0; }')
const minifiedJSON = minifyJSON('{ "name": "test" }')
```

## [Related](#related)

- [Build Plugins](https://unhead.unjs.io/docs/head/guides/build-plugins/overview) - Vite and Webpack build optimizations
- [Validate Plugin](https://unhead.unjs.io/docs/head/guides/plugins/validate) - Catch common SEO and head tag mistakes
- [Inner Content](https://unhead.unjs.io/docs/head/guides/core-concepts/inner-content) - Working with innerHTML and textContent

[Edit this page](https://github.com/unjs/unhead/edit/main/docs/head/1.guides/plugins/minify.md)

[Markdown For LLMs](https://raw.githubusercontent.com/unjs/unhead/refs/heads/main/docs/head/1.guides/plugins/minify.md)

Did this page help you?

[Infer SEO Meta Auto-generate og:title, og:description, and twitter:card from existing title and description. Reduce duplicate meta tag definitions.](https://unhead.unjs.io/docs/head/guides/plugins/infer-seo-meta-tags) [Validate Catch common SEO, performance, and head tag mistakes. Validates URLs, meta tags, Open Graph, Twitter Cards, web vitals anti-patterns, and detects typos with fuzzy matching.](https://unhead.unjs.io/docs/head/guides/plugins/validate)

On this page

- [What Does This Plugin Do?](#what-does-this-plugin-do)
- [How Do I Set Up the Plugin?](#how-do-i-set-up-the-plugin)
- [What Options Can I Configure?](#what-options-can-i-configure)
- [Build-Time Minification](#build-time-minification)
- [Standalone Minifier Utilities](#standalone-minifier-utilities)
- [Related](#related)

[GitHub](https://github.com/unjs/unhead) [ Discord](https://discord.com/invite/275MBUBvgP)

[ /llms.txt](https://unhead.unjs.io/llms.txt)

[Part of the UnJS ecosystem](https://unjs.io/)

### Head Management

- [Getting Started](https://unhead.unjs.io/docs/typescript/head/guides/get-started/overview)
- [useHead](https://unhead.unjs.io/docs/typescript/head/api/composables/use-head)
- [useSeoMeta](https://unhead.unjs.io/docs/typescript/head/api/composables/use-seo-meta)
- [useHeadSafe](https://unhead.unjs.io/docs/typescript/head/api/composables/use-head-safe)
- [useScript](https://unhead.unjs.io/docs/typescript/head/api/composables/use-script)

### Schema.org

- [Getting Started](https://unhead.unjs.io/docs/typescript/schema-org/guides/get-started/overview)
- [useSchemaOrg](https://unhead.unjs.io/docs/typescript/schema-org/api/composables/use-schema-org)
- [Nodes](https://unhead.unjs.io/docs/typescript/schema-org/guides/core-concepts/nodes)
- [Recipes](https://unhead.unjs.io/docs/typescript/schema-org/guides/recipes/identity)

### Guides

- [Titles](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/titles)
- [Streaming SSR](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/streaming)
- [DOM Events](https://unhead.unjs.io/docs/typescript/head/guides/core-concepts/dom-event-handling)
- [Plugins](https://unhead.unjs.io/docs/typescript/head/guides/plugins/template-params)

### Tools

- [Meta Tag Generator](https://unhead.unjs.io/tools/meta-tag-generator)
- [OG Image Generator](https://unhead.unjs.io/tools/og-image-generator)
- [Schema.org Generator](https://unhead.unjs.io/tools/schema-generator)
- [Capo.js Analyzer](https://unhead.unjs.io/tools/capo-analyzer)

### Articles

- [What is Capo.js?](https://unhead.unjs.io/learn/guides/what-is-capo)

### Research

- [State of <head> in 2026](https://unhead.unjs.io/learn/research/state-of-head-2026)
- [Streaming Head Performance](https://unhead.unjs.io/learn/research/streaming-head-performance)
- [Capo.js Performance Research](https://unhead.unjs.io/learn/research/capo-performance-research)

Copyright © 2025-2026 Harlan Wilton - [MIT License](https://github.com/unjs/unhead/blob/main/license)