Autoprefixer CSS Online

Autoprefixer CSS Online is the web-based version of the popular Autoprefixer PostCSS plugin that automatically adds vendor prefixes to CSS rules based on the current browser compatibility data from Can I Use. Developers paste unprefixed CSS into the input panel, select the target browsers using the Browserslist syntax (for example, a market share threshold of last 2 versions), and the tool instantly generates the prefixed output. Vendor prefixes like -webkit-, -moz-, -ms-, and -o- are automatically added to properties that require them, including transforms, transitions, animations, flexbox, grid, masks, and appearance. This ensures CSS works consistently across Chrome, Firefox, Safari, Edge, and older browser versions without developers needing to memorize which properties require which prefixes. The online version is useful for one-off checks without setting up a PostCSS build pipeline in the local development environment.