HTMLMinifier is a highly configurable, well-tested, Javascript-based HTML minifier, with lint-like capabilities.

See corresponding blog post for all the gory details of how it works, description of each option, testing results and conclusions.

Test suite is available online.

Also see corresponding Ruby wrapper, and for Node.js, Grunt plugin, Gulp module, and Koa middleware wrapper.

How does HTMLMinifier compare to another solution — HTML Minifier from Will Peavy (1st result in google search for "html minifier") as well as htmlcompressor.com?

Site	Original size (KB)	HTMLMinifier (KB)	Will Peavy (KB)	htmlcompressor.com (KB)
HTMLMinifier page	48.8	37.3	43.3	41.9
ES6 table	117.9	79.9	92	91.9
MSN	156.6	133	145	138.3
Stackoverflow	200.4	159.5	168.3	163.3
Amazon	245.9	206.3	225	218.5
Wikipedia	401.4	380.6	396.3	n/a
Eloquent Javascript	869.5	830	872	n/a

Options Quick Reference

Option	Description	Default
removeComments	Strip HTML comments	false
removeCommentsFromCDATA	Strip HTML comments from scripts and styles	false
removeCDATASectionsFromCDATA	Remove CDATA sections from script and style elements	false
collapseWhitespace	Collapse white space that contributes to text nodes in a document tree.	false
conservativeCollapse	Always collapse to 1 space (never remove it entirely). Must be used in conjunction with collapseWhitespace=true	false
preserveLineBreaks	Always collapse to 1 line break (never remove it entirely) when whitespace between tags include a line break. Must be used in conjunction with collapseWhitespace=true	false
collapseBooleanAttributes	Omit attribute values from boolean attributes	false
removeAttributeQuotes	Remove quotes around attributes when possible.	false
removeRedundantAttributes	Remove attributes when value matches default.	false
useShortDoctype	Replaces the doctype with the short (HTML5) doctype	false
removeEmptyAttributes	Remove all attributes with whitespace-only values	false
removeScriptTypeAttributes	Remove type="text/javascript" from script tags. Other type attribute values are left intact.	false
removeStyleLinkTypeAttributes	Remove type="text/css" from style and link tags. Other type attribute values are left intact.	false
removeOptionalTags	Remove unrequired tags	false
removeIgnored	Remove all tags starting and ending with <%, %>, <?, ?>	false
removeEmptyElements	Remove all elements with empty contents	false
lint	Toggle linting	false
keepClosingSlash	Keep the trailing slash on singleton elements	false
caseSensitive	Treat attributes in case sensitive manner (useful for SVG; e.g. viewBox)	false
minifyJS	Minify Javascript in script elements and on* attributes (uses UglifyJS)	false (could be true, false, Object (options))
minifyCSS	Minify CSS in style elements and style attributes (uses clean-css)	false (could be true, false, Object (options))
minifyURLs	Minify URLs in various attributes (uses relateurl)	false (could be Object (options))
ignoreCustomComments	Array of regex'es that allow to ignore certain comments, when matched	[ ]
processScripts	Array of strings corresponding to types of script elements to process through minifier (e.g. text/ng-template, text/x-handlebars-template, etc.)	[ ]
maxLineLength	Specify a maximum line length. Compressed output will be split by newlines at valid HTML split-points.
customAttrAssign	Arrays of regex'es that allow to support custom attribute assign expressions (e.g. '<div flex?="{{mode != cover}}"></div>')	[ ]
customAttrSurround	Arrays of regex'es that allow to support custom attribute surround expressions (e.g. <input {{#if value}}checked="checked"{{/if}}>)	[ ]
customAttrCollapse	Regex that specifies custom attribute to strip newlines from (e.g. /ng\-class/)

Chunks of markup can be ignored by wrapping them with <!-- htmlmin:ignore -->.

Installation Instructions

From NPM for use as a command line app:

npm install html-minifier -g

From NPM for programmatic use:

npm install html-minifier

From Git:

git clone git://github.com/kangax/html-minifier.git
cd html-minifier
npm link .

Usage

For command line usage please see html-minifier --help

Node.js

var minify = require('html-minifier').minify;
var result = minify('<p title="blah" id="moo">foo</p>', {
  removeAttributeQuotes: true
});
result; // '<p title=blah id=moo>foo</p>'

Running benchmarks

Benchmarks for minified HTML:

node benchmark.js