CSS and Design Tools

CSS Beautifier / Formatter

Format CSS with a self-hosted Prettier parser, customize indentation and line width, or minify through the existing CSSO engine. Source is never executed.

Your content stays on your device Free, with no account

Readable CSS. Local parsing.Source is never executed

CSS sourceUp to 200,000 UTF-16 source units. Plain CSS, including supported CSS nesting; this is not a Sass/Less compiler. Source is never applied to this page. Newlines normalize to LF.

Operation

Indent width

Preferred line width

Indent with tabs

PROCESSED SOURCE

CSS output · never executed

Paste CSS to begin.

Prettier changes layout, not a guarantee of browser compatibility or semantic validity. CSSO optimizes syntax/values with structural merging disabled and may reject modern syntax such as CSS nesting that the formatter supports; test minified output. URL and @import references are never fetched. Formatting preserves comments; minification retains /*! notices. Preferred line width is a target, not a hard limit.

A FEW SIMPLE STEPS

How to use CSS Beautifier / Formatter

Paste CSS or load the synthetic example. Select Beautify or Minify.
For beautifying, choose indent width, tabs and preferred line width. Minification reuses the existing CSSO engine.
Choose Process CSS. Cancel or edit to terminate obsolete local work. Syntax errors do not produce output.
Review output before copying or downloading it; formatting is not a browser compatibility or full semantic validation check.

PRIVATE BY DESIGN

Why use this tool?

CSS source is parsed in a local worker, never executed or sent to a server. No URL/import is fetched and no source history is stored.

Tool inputs stay in your browser. Only your theme preference is saved on this device.

A few things worth knowing

Which engines are used?

Prettier 3.9.10 with its CSS/PostCSS plugin for formatting. Minification reuses TheBrowserBox’s existing CSSO engine with structural rule merging disabled. Both libraries are self-hosted with their licenses.

Is my CSS executed?

No. Source remains inert text. Previews do not apply it; URLs and imports are not resolved. This is plain CSS formatting/minification, not Sass/Less compilation or a semantic browser-support audit.

What limits and formatting choices apply?

At most 200,000 UTF-16 source units and a 10-second worker timeout. Indentation 1–8, preferred width 40–160, optional tabs. Preferred width is not a hard maximum. Browser textarea line endings normalize to LF. Prettier retains comments; CSSO retains special /*! notices, but review other license forms.

How to use CSS Beautifier / Formatter

Why use this tool?

A few things worth knowing

Related tools

HTML / CSS / JavaScript Minifier

CSS Gradient Generator

Box Shadow Generator