JS Beautifier
Beautify minified or messy JavaScript into readable code. It runs entirely on your device — nothing is uploaded.
Example
Beautify minified or messy JavaScript into readable code.
How it works
Prettier parses and re-prints your JavaScript, turning dense or minified code into clean, indented source.
Good to know
JS Beautifier takes minified, one-line, or inconsistently formatted JavaScript and re-prints it as clean, indented, readable source using the Prettier engine. Because Prettier actually parses your code into a syntax tree and prints it back out, the result is far more than added whitespace — line breaks, indentation, quote style, and spacing all follow consistent rules. It is aimed at developers reverse-engineering a bundled script, reviewing a third-party snippet, or just tidying up code that arrived as an unreadable wall of text.
Reach for it when you have pasted production JavaScript (for example from a built .js bundle or a copied inline script) and need to read or debug it, when a teammate sends formatting-mangled code, or when you want a quick, consistent layout without setting up a local toolchain. Everything runs in your browser, so it is safe to paste code from private or internal projects.
When reading the output, remember that beautifying restores structure but does not undo minification of names — variables shortened to a, b, or t stay shortened, since that information is lost during minification. The formatter only changes how the code is laid out; it never changes what the code does. Use the indentation and bracket alignment to trace scope and control flow, not to recover original identifier names.
A practical caveat: Prettier needs syntactically valid JavaScript to parse, so truly broken or partial snippets may fail to format until the syntax error is fixed. It also reformats to its own opinionated style rather than matching any custom config, so treat the output as a readable reference rather than a drop-in replacement for code governed by your project's own lint rules.
Frequently asked questions
Is my data uploaded anywhere?
No — everything runs in your browser. Your code never leaves your device, so it's safe for private work and runs offline once loaded.
Is this tool free?
Yes, completely free with no sign-up and no limits.
People also ask
What is the difference between beautifying and unminifying JavaScript?
Beautifying restores readable formatting such as indentation, line breaks, and spacing, but it cannot recover information that minification permanently discarded, like original variable names or removed comments. So beautified code is easier to read, but shortened identifiers stay shortened.
Does JS Beautifier work on JSX or TypeScript?
This tool is tuned for standard JavaScript via Prettier's babel parser. JSX often works because Babel understands it, but TypeScript-specific syntax may not format correctly here — a dedicated TypeScript Formatter is better for that.
Will beautifying change how my JavaScript runs?
No. Formatting only alters whitespace, line breaks, and stylistic choices like quotes; it does not change the program's logic or behavior, since the code is parsed and re-printed with the same meaning.
Why did my code fail to beautify?
Prettier must parse valid JavaScript to reformat it, so a syntax error, an incomplete snippet, or non-JavaScript content will cause it to stop. Fixing the reported syntax issue usually resolves it.
Can I beautify a very large minified bundle?
You can paste large files since processing happens locally in your browser, but performance depends on your device's memory and CPU. Extremely large bundles may be slow to parse and re-print.
Does this tool add or change semicolons and quote styles?
Yes. As an opinionated formatter, Prettier normalizes details such as semicolons, quote style, and trailing commas to a consistent default, rather than preserving your original stylistic choices.
Is beautifying the same as running Prettier locally?
It uses the same Prettier engine, so the output is comparable, but this version applies default options rather than reading a project's custom .prettierrc configuration. Results may differ slightly from a configured local setup.
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