#html #compress #minifier #js #css


Extremely fast and smart HTML + JS + CSS minifier

26 releases

0.4.10 Apr 16, 2021
0.4.3 Feb 6, 2021
0.3.10 Dec 18, 2020
0.3.9 Nov 13, 2020
0.3.5 Jul 30, 2020

#10 in Build Utils

Download history 141/week @ 2021-01-20 169/week @ 2021-01-27 218/week @ 2021-02-03 423/week @ 2021-02-10 290/week @ 2021-02-17 98/week @ 2021-02-24 217/week @ 2021-03-03 207/week @ 2021-03-10 152/week @ 2021-03-17 204/week @ 2021-03-24 228/week @ 2021-03-31 197/week @ 2021-04-07 225/week @ 2021-04-14 150/week @ 2021-04-21 103/week @ 2021-04-28 179/week @ 2021-05-05

917 downloads per month
Used in inliners

MIT license

49K SLoC


An HTML minifier meticulously optimised for both speed and effectiveness written in Rust. Comes with native bindings to Node.js, Python, Java, and Ruby.

  • Advanced minification strategy beats other minifiers with only one pass.
  • Uses zero memory allocations, SIMD searching, direct tries, and lookup tables.
  • Well tested with a large test suite and extensive fuzzing.
  • Natively binds to esbuild for super fast JS and CSS minification.


Comparison with html-minfier and minimize, run on the top web pages. See the breakdown here.

Chart showing speed of HTML minifiers Chart showing effectiveness of HTML minifiers



Precompiled binaries are available for x86-64 Linux, macOS, and Windows.


Linux | macOS | Windows


Use the --help argument for more details.

minify-html --src /path/to/src.html --out /path/to/output.min.html --css --js


minify-html = { version = "0.4.10", features = ["js-esbuild"] }

Building with the js-esbuild feature requires the Go compiler to be installed as well, to build the JS and CSS minifier.

If the js-esbuild feature is not enabled, cfg.minify_js and cfg.minify_css will have no effect.


Check out the docs for API and usage examples.

  • Package: @minify-html/js
  • Binding: N-API
  • Platforms: Linux, macOS, Windows; Node.js 8.6.0 and higher

Using npm:

npm i @minify-html/js

Using Yarn:

yarn add @minify-html/js
const minifyHtml = require("@minify-html/js");

const cfg = minifyHtml.createConfiguration({ minifyJs: false, minifyCss: false });
const minified = minifyHtml.minify("<p>  Hello, world!  </p>", cfg);

// Alternatively, minify in place to avoid copying.
const source = Buffer.from("<p>  Hello, world!  </p>");
// This is a Buffer representing a slice of `source`, not newly allocated memory.
const minified = minifyHtml.minifyInPlace(source, cfg);

minify-html is also available for TypeScript:

import * as minifyHtml from "@minify-html/js";
import * as fs from "fs";

const cfg = minifyHtml.createConfiguration({ minifyJs: false, minifyCss: false });
const minified = minifyHtml.minify("<p>  Hello, world!  </p>", cfg);
// Or alternatively:
const minified = minifyHtml.minifyInPlace(fs.readFileSync("source.html"), cfg);

Add as a Maven dependency:

import in.wilsonl.minifyhtml.Configuration;
import in.wilsonl.minifyhtml.MinifyHtml;
import in.wilsonl.minifyhtml.SyntaxException;

Configuration cfg = new Configuration.Builder()

try {
    String minified = MinifyHtml.minify("<p>  Hello, world!  </p>", cfg);
} catch (SyntaxException e) {

// Alternatively, minify in place:
assert source instanceof ByteBuffer && source.isDirect();
MinifyHtml.minifyInPlace(source, cfg);
  • Package: minify-html
  • Binding: PyO3
  • Platforms: Linux, macOS, Windows; Python 3.7 and higher

Add the PyPI project as a dependency and install it using pip or pipenv.

import minify_html

    minified = minify_html.minify("<p>  Hello, world!  </p>", minify_js=False, minify_css=False)
except SyntaxError as e:
  • Package: minify_html
  • Binding: Rutie
  • Platforms: Linux, macOS; Ruby 2.5 and higher

Add the library as a dependency to Gemfile or *.gemspec.

require 'minify_html'

print MinifyHtml.minify("<p>  Hello, world!  </p>", { :minify_js => false, :minify_css => false })


Note that many of the minification done can result in HTML that will not pass validation, but remain interpreted and rendered correctly by the browser; essentially, the laxness of the browser is taken advantage of for better minification.


minify-html has advanced context-aware whitespace minification that does things such as:

  • Leave whitespace untouched in pre and code, which are whitespace sensitive.
  • Trim and collapse whitespace in content tags, as whitespace is collapsed anyway when rendered.
  • Remove whitespace in layout tags, which allows the use of inline layouts while keeping formatted code.


There are three whitespace minification methods. When processing text content, minify-html chooses which ones to use depending on the containing element.

Collapse whitespace

Applies to: any element except whitespace sensitive elements.

Reduce a sequence of whitespace characters in text nodes to a single space (U+0020).

Destroy whole whitespace

Applies to: any element except whitespace sensitive, content, content-first, and formatting elements.

Remove any text nodes between tags that only consist of whitespace characters.

Trim whitespace

Applies to: any element except whitespace sensitive and formatting elements.

Remove any leading/trailing whitespace from any leading/trailing text nodes of a tag.


Element types

minify-html recognises elements based on one of a few ways it assumes they are used. By making these assumptions, it can apply optimal whitespace minification strategies.

Group Elements Expected children
Formatting a, strong, and others Formatting elements, text.
Content h1, p, and others Formatting elements, text.
Layout div, ul, and others Layout elements, content elements.
Content-first label, li, and others Like content but could be layout with only one child.
Formatting elements

Whitespace is collapsed.

Formatting elements are usually inline elements that wrap around part of some text in a content element, so its whitespace isn't trimmed as they're probably part of the content.

Content elements

Whitespace is trimmed and collapsed.

Content elements usually represent a contiguous and complete unit of content such as a paragraph. As such, whitespace is significant but sequences of them are most likely due to formatting.

Layout elements

Whitespace is trimmed and collapsed. Whole whitespace is removed.

These elements should only contain other elements and no text. This makes it possible to remove whole whitespace, which is useful when using display: inline-block so that whitespace between elements (e.g. indentation) does not alter layout and styling.

Content-first elements

Whitespace is trimmed and collapsed.

These elements are usually like content elements but are occasionally used like a layout element with one child. Whole whitespace is not removed as it might contain content, but this is OK for using as layout as there is only one child and whitespace is trimmed.



Optional closing tags are removed.


Any entities in attribute values are decoded, and then the shortest representation of the value is calculated and used:

  • Double quoted, with any " encoded.
  • Single quoted, with any ' encoded.
  • Unquoted, with "/' first character (if applicable), any >, and any whitespace encoded.

class and d attributes have their whitespace (after any decoding) trimmed and collapsed.

Boolean attribute values are removed. Some other attributes are completely removed if their value is empty or the default value after any processing.

type attributes on script tags with a value equaling a JavaScript MIME type are removed.

If an attribute value is empty after any processing, everything but the name is completely removed (i.e. no =), as an empty attribute is implicitly the same as an attribute with an empty string value.

Spaces are removed between attributes if possible.


Entities are decoded if they're valid and shorter or equal in length when decoded.

Numeric entities that do not refer to a valid Unicode Scalar Value are replaced with the replacement character.

If an entity is unintentionally formed after decoding, the leading ampersand is encoded, e.g. &&#97;&#109;&#112;; becomes &ampamp;. This is done as &amp is equal to or shorter than all other entity representations of characters part of an entity ([&#a-zA-Z0-9;]), and there is no other conflicting entity name that starts with amp.

Note that it's possible to get an unintentional entity after removing comments, e.g. &am<!-- -->p; minify-html will not encode the leading ampersand.


Comments are removed.


Bangs, processing instructions, and empty elements are not removed as it is assumed there is a special reason for their declaration.


Issues and contributions

Pull requests and any contributions welcome!

If minify-html did something unexpected, misunderstood some syntax, or incorrectly kept/removed some code, raise an issue with some relevant code that can be used to reproduce and investigate the issue.


~24K SLoC