Clean up HTML, CSS, JSON, and JavaScript so code stops fighting your eyes
Code arrives from code generators, build output, and copy-pasted snippets in every possible state of disrepair: one-line HTML that wraps unpredictably, CSS with mixed indentation, minified JavaScript that is impossible to inspect. This formatter pretty-prints four of the most common web languages — HTML, CSS, JSON, and JavaScript — with consistent indentation and predictable line breaks, turning soup into something you can actually read, review, and debug.
Reach for it when you inherit unreadable markup, need to inspect a bundled or minified asset, or want a uniform style before committing a snippet to a codebase.
Format Code in Five Steps
- Select the language — HTML, CSS, JSON, or JavaScript — that matches your input.
- Paste the raw code into the input area.
- Click Format and confirm the output uses consistent indentation and one-element-per-line nesting.
- Copy the result back into your editor, or re-run on the formatted output after further edits to keep it clean.
- Compare the formatted output against the original to verify nothing but whitespace changed before committing it.
Real Example: Minified HTML Becomes Readable Markup
An email template arrives as a single 2,000-character line. Formatting it as HTML splits every element onto its own line with proper nesting, so you can finally see which div closes where and spot the missing alt attribute. The same routine applies to CSS where each rule and property lands on its own line, and to JavaScript where nested callbacks and object literals become traceable.
| Input | Output |
|---|---|
<div><p>Hi</p><span>There</span></div> | <div> |
Formatting Habits That Keep Code Clean
- Pick the right language mode — HTML, CSS, JSON, and JavaScript have different rules; the wrong mode produces misleading indentation.
- Format before reviewing — run a diff between the formatted old and new versions so reviewers see real changes, not whitespace noise.
- Do not reformat untouched files — reformatting a file with no other changes creates review noise; format only the code you are actually editing.
- Keep templates readable from the start — a formatted template is easier to maintain than one you must decode on every visit.
- Check attribute quoting — formatting normalizes whitespace but does not fix unquoted attributes; those are a separate correctness issue.
When Formatting Saves Real Time
- Inspecting build output — pretty-print minified bundles to trace which markup or style rule broke a page.
- Inheriting code — clean up a template or stylesheet you just took over before making changes.
- Pasting into docs — format snippets so they render well in tickets, wikis, and pull request descriptions.
- Reviewing generated code — read the output of code generators with the same eyes you use on hand-written code.
Frequently Asked Questions
Which languages does the formatter support?
HTML, CSS, JSON, and JavaScript. Each has its own mode so indentation and line-breaking rules match the language, rather than applying one generic algorithm.
Does formatting change how the code behaves?
No. Formatting only rearranges whitespace, which is insignificant in all four languages. The formatted code parses and runs exactly like the input.
Can it un-minify a production JavaScript bundle?
It can make a minified script readable, but minification also renames variables and strips comments, which no formatter can restore. Expect readable structure, not original names.
Why does my HTML output still look wrong?
Unclosed tags or mismatched quotes confuse any formatter. Run the markup through a validator first, or check that the input is well-formed before formatting.
What indentation does the tool use?
Two spaces per level, the most common convention across web projects. It is deliberately boring so results match what most linters and editors produce.
Is this the same as the JSON formatter tool?
The JSON mode here and the dedicated JSON formatter both pretty-print JSON, but the dedicated tool also validates with precise error positions. Use it when correctness is the priority.
Will it reformat embedded CSS and JavaScript inside HTML?
The HTML mode formats the markup structure. Embedded <style> and <script> blocks are preserved; format them separately with the CSS or JavaScript mode for best results.
Does the tool handle template literals and JSX?
JavaScript template literals are preserved as-is. JSX is not a supported language mode, so treat JSX-heavy files with the JavaScript mode and accept its limitations.