Autoprefixer

What is CSS Autoprefixer?

Autoprefixer is an essential PostCSS plugin that automatically adds vendor prefixes to your CSS code, ensuring cross-browser compatibility.

Our online Autoprefixer tool provides a free, fast, and secure way to prefix your CSS without installing any software. All processing happens in your browser, ensuring your code remains private and secure.

Why Use Autoprefixer?

Modern CSS features often require vendor prefixes for older browsers. Writing these manually is:

• Time-consuming - Manually adding prefixes for every property wastes valuable development time
• Error-prone - Easy to forget prefixes or use outdated ones
• Hard to maintain - Browser support changes constantly, requiring frequent updates
• Bloated - You might add unnecessary prefixes for browsers you don't need to support

Autoprefixer solves these problems by automatically adding only the prefixes you need based on your target browsers.

Key Features

• Real-time Processing - See prefixed CSS instantly as you type (with smart debouncing)
• Latest Browser Data - Always uses up-to-date compatibility information from Can I Use
• Customizable Browser Targets - Specify exactly which browsers to support using Browserslist queries
• Version Selection - Choose any version of PostCSS or Autoprefixer for compatibility testing
• Module Caching - Faster subsequent processing with intelligent caching
• Global Browsers Coverage - See the global browser coverage for your CSS
• 100% Client-Side - Your CSS never leaves your browser - completely private and secure
• No Installation Required - Use immediately without npm, Node.js, or any setup
• Free Forever - No registration, no limits, no hidden costs

How to Use This Tool

1. Paste Your CSS - Copy your CSS code into the input editor
2. Configure Browsers - Set your target browsers (default: "last 4 versions")
3. Get Prefixed CSS - The output appears automatically with all necessary vendor prefixes
4. Copy & Use - Click "Copy Output" and paste into your project

Example: Before & After

.example {
  display: flex;
  transition: all 0.5s;
  user-select: none;
}

.example {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-transition: all 0.5s;
  transition: all 0.5s;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

Common Use Cases

• Quick Testing - Test if your CSS needs prefixes before adding to build tools
• Learning - Understand which CSS properties require vendor prefixes
• Small Projects - Add prefixes without setting up a build system
• Legacy Browser Support - Ensure compatibility with older browsers
• Code Snippets - Prefix CSS for CodePen, JSFiddle, or documentation
• Email Templates - Generate prefixed CSS for email clients

Popular Browserslist Queries

Frequently Asked Questions