JavaScript Beautifier Online Free
Paste JavaScript, TypeScript, CSS, or HTML and format it instantly using Prettier. Consistent indentation, spacing, and style in one click. Runs in your browser — no upload, no signup.
⏱ 6 min read · Complete guide below
JavaScript / Code Beautifier
How to Beautify Code
- 1Paste your code into the input box.
- 2Select the correct Language (JavaScript, TypeScript, CSS, or HTML) and your preferred indent size.
- 3Click Beautify. Prettier parses the code and reformats it with consistent style.
- 4Click Copy to copy the formatted result to your clipboard.
Why Use a Code Formatter?
Consistent code formatting reduces cognitive load when reading and reviewing code. When every developer on a team uses the same formatter, diffs only show real changes — not whitespace noise — which makes code reviews faster and more meaningful. Prettier is the industry-standard choice for JavaScript projects precisely because it is opinionated: there are very few settings to argue about, so teams can focus on logic rather than style debates.
Beautifying vs Minifying — Opposite Directions
Formatting and minifying are two opposite transformations of the same code. A beautifieradds whitespace, line breaks, and consistent indentation to make code easy for humans to read and maintain. A minifier does the reverse: it strips out every non-essential space, newline, and comment — and often shortens variable names — to make the file as small as possible for fast delivery to a browser. Both preserve exactly what the code does; they only change how it looks. That is why this tool can take heavily minified JavaScript, where everything sits on one enormous line, and expand it back into clean, readable structure — a genuinely useful step when you need to inspect or debug a production bundle.
Why Prettier Is the Standard
This beautifier is powered by Prettier, the same formatter that runs in millions of editors and continuous-integration pipelines. Prettier's defining trait is that it is opinionated: rather than exposing dozens of style options to argue over, it makes most decisions for you and reformats code to a single consistent standard. This matters more than it sounds. When an entire team formats with the same tool, version-control diffs show only real logic changes instead of whitespace noise, code reviews get faster, and the endless bikeshedding about tabs, quotes, and brace placement simply disappears. Running your code through the same engine here gives you output that will match those team standards.
It All Runs in Your Browser
A common and reasonable worry with online code tools is privacy — pasting proprietary source into a website that ships it off to a server. This beautifier avoids that entirely by loading Prettier's standalone WebAssembly build and running it locally in your browser. Your code is parsed and reformatted on your own machine and is never transmitted over the network, which means it is safe to use with private or commercial code. A useful side effect is that the tool keeps working even if you go offline after the page has loaded, since there is no server round-trip involved in the formatting itself.
Tips for Formatting Code
Match Your Project Config
If your project uses a .prettierrc file, match the tab width here before copying the formatted code back. Mismatched settings will cause your formatter and CI checks to disagree.
Format Before Diffing
When comparing two versions of a file, format both through the beautifier first. This normalises whitespace differences so the diff only shows meaningful code changes.
TypeScript Needs Its Own Parser
Select TypeScript (not JavaScript) for files with type annotations, interfaces, enums, or generics. Using the JavaScript parser on TypeScript code will produce a parse error.
Use With the JSON Formatter
For JSON embedded in JavaScript (like a config object), extract it first, format it with the JSON Formatter, then paste it back. Prettier handles inline JSON but can be picky about trailing commas.
Frequently Asked Questions
What languages does the beautifier support?
The tool supports JavaScript (ES2022+), TypeScript, CSS (including SCSS-compatible syntax), and HTML. Select the correct language from the dropdown before formatting — each language uses a different Prettier parser internally.
What formatting engine does this tool use?
It uses Prettier — the same formatting engine used by millions of developers in VS Code, WebStorm, and CI pipelines worldwide. Prettier enforces consistent style: consistent quote style, semicolons, bracket spacing, line length wrapping, and indentation. The WASM build of Prettier runs entirely in your browser — no code is sent to a server.
Can I format minified or obfuscated JavaScript?
Minified code (whitespace stripped) formats perfectly — Prettier fully parses the AST and re-emits it with consistent indentation. Obfuscated code (variable names replaced with gibberish like a, b, _0x1a2b) also formats, but the result is still obfuscated — formatting only improves whitespace and structure, it does not deobfuscate or rename identifiers.
What does the Indent option control?
It sets the number of spaces used for each level of indentation. 2 spaces is the default Prettier setting and is popular in JavaScript and TypeScript projects. 4 spaces is common in Python and some older JavaScript codebases. Tab characters are not currently offered — Prettier converts tabs to spaces in the output.
Why does my code show a parse error?
Parse errors usually mean either the wrong language is selected (for example, choosing JavaScript for TypeScript-specific syntax like type annotations) or the code has a genuine syntax error. Check that the language dropdown matches your code and that there are no unclosed brackets or missing semicolons where required.
Is my code sent to a server?
No. Prettier's standalone WASM build loads in your browser and runs locally. Your code is never transmitted over the network. The tool works correctly even if you disconnect from the internet after the page loads.
What is the difference between beautifying and minifying code?
They are opposite operations. Beautifying adds whitespace and consistent indentation to make code readable for humans, while minifying removes every non-essential space, newline, and comment to make the file as small as possible for fast loading. Both keep the code's behaviour identical. This tool beautifies, so it is ideal for turning a cramped or minified file back into clean, readable structure.
Can I read minified production code with this?
Yes — that is one of its most useful jobs. Paste minified JavaScript, where everything is squeezed onto one line, and the beautifier fully parses it and re-emits it with proper indentation and line breaks, making it far easier to inspect or debug. Note that if the code was also obfuscated (variable names replaced with gibberish), formatting restores the structure but cannot recover the original meaningful names.
Will the formatted code match my team's style?
It will match standard Prettier output, which is the style used by a very large share of JavaScript and TypeScript teams. If your project has a .prettierrc configuration, set the indent size here to match it before copying the result back, so your formatting agrees with your project's CI checks. Because Prettier is intentionally opinionated with few options, its default output is already consistent with most teams' conventions.
Why am I getting a parse error?
The two usual causes are selecting the wrong language or having a genuine syntax error. If your code uses TypeScript features like type annotations or interfaces, you must choose TypeScript rather than JavaScript, or the parser will reject it. Otherwise, check for unclosed brackets, missing commas, or stray characters. A formatter needs syntactically valid code to build its internal representation, so it cannot reformat code that does not parse.