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.
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.
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.