Free HTML/CSS/Markdown Formatter & Minifier

How this tool computes its result

Three independent regex pipelines, one per mode (HTML/CSS/Markdown), each with a separate format and minify function — there is no shared AST. HTML format tokenizes on tag boundaries and tracks an indent counter (incrementing after an opening tag, decrementing on a closing tag, leaving it unchanged for anything matching `/\/>$/`, `<!`, or `<?`). HTML minify strips comments and collapses inter-tag/duplicate whitespace. CSS format strips comments, puts each brace/semicolon/colon on its own normalized line, then re-indents by brace depth; CSS minify strips comments and all non-essential whitespace around `{ } : ; ,`. Markdown format trims trailing whitespace and collapses runs of blank lines to one; Markdown minify trims every line and removes all blank lines entirely.

Worked example

HTML mode, input `<div><p>Hi</p></div>` formats to: ``` <div> <p> Hi </p> </div> ``` (the bare text "Hi" is emitted at the current indent level since it is not itself a tag token) and minifies back to `<div><p>Hi</p></div>` since there was no extra whitespace between tags to strip.

When not to use this tool

The HTML formatter is a naive tag-boundary tokenizer, not a real parser — it does not recognize HTML5 void elements without a trailing slash (`<br>`, `<img src="x">`), so it increments the indent level after them expecting a closing tag that never comes, which throws off indentation for the rest of the document.

Common mistakes

• - Feeding void elements without self-closing slashes into the HTML formatter — `isSelfClosing` only checks for a trailing `/>`, `<!`, or `<?`, so bare `<br>`/`<img>` tags increment indent and are never decremented back.
• - Using CSS values with embedded colons, like `content: "a:b"` or URLs with ports — the formatter's blanket `\s*:\s*` normalization runs on every colon in the file, not just property/value separators.
• - Expecting minify to perform real minification (shortening color values, removing redundant quotes); it only strips whitespace and comments, it does not do semantic CSS/HTML compression.

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