Code Beautifier

Web & Markup

Markup work is mostly pipeline work. Content arrives as HTML and needs to be Markdown, a designer's HTML needs to become JSX, a stylesheet has to ship minified but stay readable in review. These tools cover both directions of that pipeline and run entirely in the browser, in an editor that keeps the syntax highlighting, bracket matching and indentation behaviour you expect from an IDE rather than a plain textarea.

Tools (12)

HTML Formatter
Clean up unformatted, messy HTML markup into well-indented, readable code with customizable line wrapping.
HTML to Markdown
Convert HTML markup, tables, lists, and formatted content back into clean, readable Markdown syntax.
Markdown to HTML
Convert Markdown documents, tables, lists, and code blocks into clean, formatted HTML markup.
CSS Beautifier
Format, organize, or minify CSS stylesheets with consistent indentation, selector spacing, and clean rule separation.
CSS Minifier
Compress and minify CSS stylesheets by removing whitespace, line breaks, and comments.
CSS to Tailwind
Heuristically map common CSS declarations to Tailwind utility classes.
JavaScript Beautifier
Format, un-minify, or compact JavaScript & TypeScript code into clean, readable scripts with custom indentation.
SVG Optimizer & CSS Data URI
Strip editor junk, comments, and redundant metadata from SVGs. Convert directly to CSS Data URI or React JSX.
User Agent Parser
Parse User-Agent strings into browser, engine, OS, and device, and spot crawlers such as GPTBot and ClaudeBot in your logs.
HTML to JSX
Convert HTML into JSX for React: className and htmlFor, camelCase SVG attributes, inline styles as objects, and void elements self-closed.
HTML Minifier
Shrink HTML by collapsing whitespace and removing comments, without touching pre, textarea, script, style, or conditional comments.
iframe Render Tester
Paste HTML and watch it render inside a sandboxed iframe at any viewport, then copy the exact embed snippet.

Minifying and beautifying are not symmetric

Beautifying minified code restores indentation but cannot recover the original names or comments, so treat it as a reading aid rather than a true reversal. Minification also has a trap specific to HTML: whitespace between inline elements is content, and deleting it changes what the page renders. HTML Minifier collapses runs of whitespace to a single space instead of removing them, and leaves pre, textarea, script and style blocks byte for byte intact.

Migrating markup between ecosystems

HTML to JSX performs the attribute renames React requires, turning class into className and for into htmlFor, camelCasing hyphenated SVG attributes, and converting an inline style string into the object form including custom properties and vendor prefixes. HTML to Markdown strips presentational markup back to content, Markdown to HTML reverses it, and CSS to Tailwind maps plain declarations onto utility classes.

Seeing the markup before you ship it

A layout bug and a script bug look identical in a page full of inherited styles. iframe Render Tester drops your markup into a sandboxed iframe with its own document, its own cascade and a viewport width you choose, so a 375px breakpoint is something you can look at without resizing the window. Each sandbox token is a switch: turn off allow-scripts and a layout that still breaks is a CSS problem, turn it back on and a form that will not submit is missing allow-forms. Run the markup through HTML Formatter first when a preview comes back blank, since an unbalanced tag renders as nothing.

Keeping assets small

SVG Optimizer removes the editor metadata, comments and redundant coordinate precision that design tools leave behind, which often halves a file with no visible change to the rendered image. CSS Minifier does the equivalent for stylesheets, and CSS Beautifier restores structure when you need to read a compiled bundle that shipped without a source map.

Cheat sheets

CSS Grid & Flexbox Reference Guide
Complete visual property matrix for modern CSS layouts: container rules, item alignments, repeat(), and minmax()

Guides

Migrating HTML to JSX without the whack-a-mole
Every attribute rename, style-object conversion, void elements, comments, and the two errors you will hit, with a converter that does the mechanical part.
Minify vs beautify: what each actually changes
Minifying removes what a browser does not need; beautifying restores layout, not meaning. When to use each, what is lost, and the HTML whitespace trap.

FAQ

Can minifying HTML change how the page looks?

It can, if the minifier removes whitespace between inline elements, because that whitespace is rendered content. A safe minifier collapses each run to a single space instead, which is why the output here never joins two inline tags together.

Can I paste a whole page of HTML and get JSX back?

Yes. Attributes are renamed, void elements are self-closed, comments become JSX comment expressions, and braces in text are escaped so they are not read as expressions. You will still need to split the result into components yourself.

Is beautifying the exact reverse of minifying?

No. Indentation and line breaks come back, but comments and original identifier names are gone for good once a minifier has removed or renamed them. Beautified output is for reading and debugging, not for restoring a lost source file.

How much does optimizing an SVG usually save?

Files exported from design tools often shrink by a third to a half, because most of the weight is editor metadata, hidden layers and coordinates carried to far more decimal places than any display can resolve.