HTML Minifier

What Is HTML Minification?

HTML minification is the process of reducing the size of an HTML document without changing how the browser renders it. An HTML minifier removes characters that exist only for developer readability: whitespace between tags, comments, optional closing tags, and redundant attribute values. The output is functionally identical to the source but smaller in byte size, which means faster downloads and quicker time-to-first-paint for users.

Browsers parse HTML into a DOM tree and discard most whitespace during that process. A sequence of spaces and line breaks between two div tags has zero visual effect on the rendered page. Comments are also ignored by the parser. Minification takes advantage of these rules, stripping what the parser would discard anyway so that it never has to be transferred over the network.

The savings from HTML minification vary by document. Heavily commented templates, server-rendered pages with deep indentation, and CMS output with inline styles often see a 15-30% size reduction from minification alone. For small documents the absolute savings are modest, but on high-traffic sites even a few kilobytes per page load add up to real bandwidth savings across millions of requests.

Why Use This HTML Minifier?

Paste your HTML and get minified output instantly. No build tools to install, no configuration files, no accounts.

HTML Minifier Use Cases

What HTML Minification Removes

A full-featured HTML minifier applies several transformations beyond whitespace removal. The table below lists the most common techniques, ordered from safest (always lossless) to most aggressive (may break edge cases if applied blindly).

Minification vs. Gzip Compression

Developers sometimes ask whether minification is still necessary when the server already applies Gzip or Brotli compression. The short answer: yes, and they work best together.

Minification reduces the input that Gzip processes, so the compressed output is smaller too. Google's PageSpeed guidelines recommend applying both. On a typical page, minification saves 15-25% of raw size and Gzip compresses the result by another 60-80%. Combined, total transfer size can drop to 10-20% of the original unminified, uncompressed document.

Code Examples

Below are working examples of HTML minification in four environments. Each example removes comments and collapses whitespace.

import { minify } from 'html-minifier-terser'

const html = `
  <div class="card">
    <!-- user profile -->
    <p>  Hello, world!  </p>
  </div>
`

const result = await minify(html, {
  collapseWhitespace: true,
  removeComments: true,
  removeRedundantAttributes: true,
  removeEmptyAttributes: true,
})
// → '<div class="card"><p>Hello, world!</p></div>'

import htmlmin

html = """
<div class="card">
  <!-- user profile -->
  <p>  Hello, world!  </p>
</div>
"""

result = htmlmin.minify(html, remove_comments=True, remove_empty_space=True)
# → '<div class="card"><p>Hello, world!</p></div>'

package main

import (
    "fmt"
    "github.com/tdewolff/minify/v2"
    "github.com/tdewolff/minify/v2/html"
)

func main() {
    m := minify.New()
    m.AddFunc("text/html", html.Minify)

    input := `<div class="card">
  <!-- user profile -->
  <p>  Hello, world!  </p>
</div>`

    result, _ := m.String("text/html", input)
    fmt.Println(result)
    // → <div class=card><p>Hello, world!</div>
}

# Install globally
npm install -g html-minifier-terser

# Minify a file
html-minifier-terser --collapse-whitespace --remove-comments input.html -o output.html

# Pipe from stdin
cat index.html | html-minifier-terser --collapse-whitespace --remove-comments

# With all common optimizations
html-minifier-terser \
  --collapse-whitespace \
  --remove-comments \
  --remove-redundant-attributes \
  --remove-empty-attributes \
  --minify-css true \
  --minify-js true \
  input.html -o output.min.html

Frequently Asked Questions