100% Client-Side • Modern JS Formatter • Zero Cloud Storage

Free JavaScript (JS) Unminifier & Formatter

Q: What is a JavaScript Unminifier and how does it work?

A JavaScript unminifier takes compressed or minified code and parses its grammar to reconstruct clean, standardized indentation and line breaks.

Q: Can an unminifier recover original variable names like userEmail?

No. When a minifier replaces variable names with short single letters, the original names are omitted from the file and can only be restored via source maps.

Deobfuscate, unminify, and beautify messy or compressed JavaScript code in your browser. Reconstructs line breaks, consistent indentation, and structural clarity for modern ES6+ scripts.

Clean Indentation ES6+ & Async/Await Ready 100% In-Browser Privacy Ctrl + Enter Shortcut

Minified Input Size 0 B 0 lines

Formatted Output Size 0 B 0 lines

Code Expansion 0 Lines expanded

Formatting Speed 0 ms 100% In-Browser

How to Unminify & Beautify JavaScript in 3 Steps

Transform unreadable single-line JavaScript into clean, indented code instantly

Paste or Upload Code

Paste minified, compressed, or packed JavaScript code into the source editor or upload a local .js file up to 5MB.

Select Format Options

Choose your desired indentation (2 spaces, 4 spaces, or Tabs), brace placement style, and maximum line wrap preferences.

Unminify & Copy

Click Unminify JavaScript (or hit Ctrl+Enter). View the full-width result, copy with one click, or download script.formatted.js.

What JavaScript Unminification Can & Cannot Do

An honest, technical guide to understanding JavaScript deobfuscation and formatting

What This Tool Restores (100% Guaranteed):

Proper Indentation: Restores nested code indentation across functions, loops, classes, and conditionals.
Line Breaks: Splits thousands of compressed statements into distinct, readable code lines.
Control Flow Clarity: Restores standard spacing around operators, parentheses, and curly braces.
Modern Syntax: Accurately formats arrow functions, async/await, classes, destructuring, and template literals.
Preserved Comments: Properly spaces and formats any copyright or license comments remaining in the code.

What Minification Irreversibly Destroys:

Mangled Variable Names: If original variables like calculateTotalPrice were mangled to a, the original names are permanently gone from the binary without a .map source map.
Stripped Comments: Any comments deleted by a minifier cannot be magically recreated because the data was completely discarded.
Dead Code: Functions or unused branches eliminated during build-time tree shaking cannot be recovered.

Production Debugging

Quickly format compressed vendor libraries, minified third-party bundles, or production scripts to identify stack traces and set breakpoints effectively.

Security & Code Auditing

Inspect external scripts, browser extensions, or untrusted JavaScript before deployment to detect malicious payloads, obfuscated data exfiltration, or backdoors.

Reverse Engineering & Learning

Study how high-performance open-source libraries or web applications structure algorithms, organize classes, and optimize asynchronous workflows.

Frequently Asked Questions

Everything you need to know about JavaScript formatting and deobfuscation

What is a JavaScript Unminifier and how does it work?

A JavaScript unminifier (or beautifier) takes compressed, single-line, or packed JavaScript code and parses its grammar to reconstruct clean, standardized indentation, line breaks, and bracket hierarchy. It makes previously unreadable code accessible to human developers for debugging and review.

Can an unminifier recover original variable names like "userEmail"?

No tool can guess original variable names if they were mangled during minification. When a minifier replaces userEmail with e, the original word is completely omitted from the delivered file. Only a valid JavaScript source map (.js.map file) contains the dictionary mapping mangled identifiers back to original names. However, unminification makes the control flow, arguments, and logic fully transparent.

Is my code sent across the internet or stored on your servers?

No. All unminification, formatting, and syntax validation occurs 100% locally in your web browser. Your proprietary logic, tokens, and scripts never touch our servers and are never saved or analyzed.

Does this formatter support modern ECMAScript (ES2022+)?

Yes. The formatter natively handles modern JavaScript syntax, including classes, arrow functions, object rest/spread properties, async/await, template literals, optional chaining (?.), and nullish coalescing (??).

What is the difference between "Collapse" and "Expand" brace styles?

The "Collapse" style (also known as 1TBS or One True Brace Style) places opening curly braces on the same line as the statement (e.g., function test() {). The "Expand" style (Allman style) places opening curly braces on a new line (e.g., function test()\n{), which is common in C# or C++ conventions.