HTML / CSS Beautifier

The HTML / CSS Beautifier re indents messy markup or styles so you can read the structure in a flash. It keeps significant whitespace in inline contexts, so the result is the same document, just formatted, which makes cascade and specificity bugs far easier to spot. Use it when a file you received is one long line, when you are auditing a stylesheet, or when you want to compare two versions more easily. The tool runs locally in your browser, so your markup and styles are never transmitted. Markup and stylesheets share a property that makes them hard to read when they arrive unformatted: their structure is defined by nesting, and nesting is invisible without indentation. Reformatting puts each element and each rule on its own level, so the hierarchy becomes something you can see rather than something you have to reconstruct while reading. That matters most when diagnosing the two classes of bug that markup and styles produce. For markup, a missing closing tag means everything after it becomes a child of the wrong element, and indentation exposes that immediately. For styles, the cascade and specificity decide which rule wins, and reading a formatted stylesheet makes the order and the selector weight visible instead of lost in a single long line. It is also the fastest preparation for a comparison, since a diff between two versions only shows meaningful changes when both sides are consistently formatted, and it is a practical way to review a file someone else handed over. Working in the browser keeps the source local.

📘 Related guide: Beautify minified JavaScript in the browser →