Code Beautifier Online
Quick answer
Paste minified or messy code and get clean, consistently indented output in one click: JavaScript via js-beautify, JSON natively, HTML and CSS with tag- and rule-aware formatting. Everything runs in your browser — no upload, no account, no queue — with 2-space, 4-space or tab indentation you can switch live.
Last updated: October 26, 2026
Minified code is everywhere once you are past the source you wrote: production bundles, CDN libraries, email templates, copy-pasted snippets from Stack Overflow answers, AI output with inconsistent spacing. Reading it raw wastes the time you were hoping to save. This beautifier turns that wall of characters back into structured, indented code in milliseconds — pick the language, paste, read. It uses the same js-beautify engine that editors and browser extensions have trusted for a decade, runs entirely client-side, and never asks for an account, because formatting someone else's code should not require handing that code to a server.
Use the tool belowCode Beautifier runs entirely in your browser, nothing you paste or type is uploaded to any server, and no account is needed.
Worked examples
Real input on the left, exactly what Code Beautifier gives back on the right. Paste either side into the tool to re-create it.
1Minified JSON config to readable form
The everyday case: a config blob from a build log or API response.
{"name":"app","version":"2.1.0","deps":{"react":"18.3.1","vite":"6.0.0"},"scripts":{"dev":"vite","build":"vite build"}}{
"name": "app",
"version": "2.1.0",
"deps": {
"react": "18.3.1",
"vite": "6.0.0"
},
"scripts": {
"dev": "vite",
"build": "vite build"
}
}Native JSON.stringify output — key order preserved, byte-exact data, parser errors reported with their real message when input is invalid.
2One-line JavaScript restored to readable form
A compressed function from a bundle or bookmarklet.
function slug(s){return s.toLowerCase().trim().replace(/[^a-z0-9]+/g,"-").replace(/^-+|-+$/g,"")}function slug(s) {
return s.toLowerCase().trim().replace(/[^a-z0-9]+/g, "-").replace(/^-+|-+$/g, "")
}Same tokens, same behavior — only whitespace and spacing changed. Safe to paste into a debugger session or a code review comment.
How do I beautify code online?
- 1
Pick the language tab: JavaScript, JSON, HTML or CSS. A realistic minified sample loads so you can see the tool work before pasting anything.
- 2
Paste your code into the left pane (or replace the sample). Formatting is live — the beautified result appears on the right as you type, debounced so long files stay smooth.
- 3
Choose indentation: 2 spaces for style-guide consistency with most modern repos, 4 spaces for classic conventions, or tabs for editor-configurable width.
- 4
Copy the output with one click. JSON errors show the exact parser message instead of a silent failure, so invalid JSON is diagnosed, not guessed at.
What this code beautifier does well
Four languages, one surface
JavaScript, JSON, HTML and CSS cover the everyday beautify jobs: bundle debugging, config inspection, email-template cleanup and design-token files. Switch language and a matching sample loads instantly — no guessing which tool handles which syntax.
The real js-beautify engine
The page loads js-beautify 1.15.1 from CDN — the same library that powers editor extensions and beautifier.io. Brace and bracket handling, operator spacing and newline preservation behave the way your editor's formatter does, because it is the same code.
JSON with real error messages
JSON is beautified natively with JSON.parse and JSON.stringify, so a trailing comma or missing quote produces the exact parser error — including position context — instead of a vague failure. The beautified output is byte-faithful to what the data actually says.
Live, debounced formatting
Output updates as you paste and type, with a short debounce so large minified bundles do not re-format on every keystroke. The loop of paste, glance, adjust indent, copy stays under a second for typical files.
Private by architecture
Formatting happens in a sandboxed iframe in your own tab. There is no upload endpoint, no processing server and no history. Proprietary bundles, internal API responses and unreleased templates can be formatted without leaving your machine.
Indentation that matches your style guide
Switch between 2 spaces, 4 spaces and tabs at any time — the whole document re-formats instantly. It is the fastest way to normalize a snippet copied from three different sources into one consistent style before committing it.
Beautifier vs formatter vs minifier
The three terms overlap, and picking the wrong one wastes a visit. Here is the honest map of what each does and where this tool sits.
| Tool type | What it does | Typical use | This tool |
|---|---|---|---|
| Beautifier | Re-indents existing code without touching structure | Reading minified bundles, cleaning pasted snippets | Yes — js-beautify, live, four languages |
| Linter / formatter (Prettier, ESLint) | Enforces configurable style rules, flags bad patterns | Team codebases, CI pipelines | No — use Prettier in your repo for enforced style |
| Minifier | Strips whitespace and shortens names for production | Deploy builds | No — this tool goes the other direction on purpose |
Beautifying is lossless for JavaScript, HTML and CSS structure: whitespace and indentation change, tokens do not. JSON beautification is byte-exact for the parsed data.
Why code gets minified, and how to read it again
Minification exists for production: whitespace removal, short variable names and bundling cut kilobytes and load time. That optimization is exactly what makes the code unreadable to humans — a single line holding a whole component. When you need to debug a production bundle, verify what a CDN library actually does, or recover the readable form of a snippet that arrived minified, you are reversing that last step, which is precisely what a beautifier does: it restores whitespace and indentation without changing what the code means.
The second everyday case is consistency. Code pasted from documentation, AI assistants and three different repos rarely agrees on indentation. Paste each fragment here, normalize to your project's indent style, and the diff you commit shows the real change instead of a whitespace storm. For pure formatting checks — what exactly changed between two versions after a reformat — the diff checker pairs naturally with this tool: beautify both, then compare.
What beautifying does and does not do
Beautifying is a whitespace operation. It re-inserts newlines and indentation, normalizes spacing around operators and braces, and leaves every token, name and string exactly as it was. It will not rename minified variables back to meaningful names (that information no longer exists in the file), and it does not fix logic errors — a missing bracket becomes a parse error in the output, not a repair.
That is also the safety story: because tokens are untouched, beautified code behaves identically to the original. It is safe to beautify a file you are about to debug, log or review. The one caveat is JSON: if the input is not valid JSON, there is nothing to beautify — the tool reports the parser error instead of guessing, which is usually the fastest way to find the actual typo in a broken config.
Questions this tool answers
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Frequently asked questions
Is this code beautifier free?
Yes — no cost, no usage limits, no account. The tool runs on the open-source js-beautify library inside your browser, so there is no server cost to pass on and no quota to track. Format a hundred files if you like.
Does my code get uploaded anywhere?
No. The formatting engine loads from CDN once, then runs entirely inside your browser tab in a sandboxed iframe. Your source and output never leave your device — you can disconnect from the network after the page loads and the tool keeps working.
What is the difference between beautifying and minifying?
They are opposites. Minifying removes whitespace to shrink files for production; beautifying re-adds whitespace to make files readable. This tool beautifies only — feeding it readable code just re-indents it consistently, it will never compress it.
Which languages can it format?
JavaScript, JSON, HTML and CSS — the languages that cover most online beautify needs. JSON is handled natively with exact parser errors; the other three use js-beautify's dedicated parsers. For SQL, the JSON and text tools on this site cover related formatting jobs.
Why did my JSON fail to beautify?
The input is not valid JSON — common causes are a trailing comma, single quotes instead of double quotes, or an unquoted key. The status line shows the exact JSON.parse error message rather than a vague failure, which usually points straight at the offending character.
Can I beautify code from a minified production bundle?
Yes, that is one of the main uses. Paste the bundle section (or the whole file if it is not too large) and the beautifier restores indentation. Note that variable names stay minified — renaming information does not survive minification — but the structure becomes readable again.