JavaScript Formatter & Minifier Online – Beautify, Compress & Optimize JS Code Free

JS Formatter & Minifier

Advanced client-side JavaScript beautify and compression tool. Format messy JS with proper indentation or minify it for production — instantly, privately, and 100% in your browser.

Free No Upload Client-Side Only

JavaScript Input

Paste your JavaScript code

Or upload a JavaScript file

Drag & drop your JavaScript file here

or browse files from your device · .js / .mjs up to 200 KB

Remove comments

Optimize code

Preserve semicolons

Validating JavaScript... 0%

JavaScript Processed Successfully

Output

How To Format & Minify JavaScript

1

Paste or Upload JS

Enter your JavaScript code directly in the textarea or drag and drop a .js file from your device.

2

Click Beautify to Format

Press Beautify to restructure your JavaScript with proper indentation, spacing, and readable formatting.

3

Click Minify to Compress

Press Minify to strip whitespace, comments, and optimize variables for smaller file sizes.

4

Preview the Result

Review the formatted or minified JavaScript output in the scrollable preview with size and line statistics.

5

Copy to Clipboard

Use the copy button to instantly copy the entire processed JavaScript to your system clipboard with one click.

6

Download JS File

Download the result as a .js file directly to your device for immediate use in your projects.

Frequently Asked Questions

The JavaScript Formatter (Beautifier) takes messy, minified, or unstructured JS code and restructures it with proper indentation, consistent spacing, aligned braces, and readable formatting. This makes the code significantly easier to read, debug, and maintain for developers.

The JavaScript Minifier uses Terser (the industry-standard minifier) to remove comments, strip whitespace, shorten variable names, and apply code optimizations. This produces a compact version of your JavaScript that loads faster and uses less bandwidth, typically reducing file size by 40-70%.

No. Terser performs AST-level transformations that preserve the exact behavior of your code. It renames only local variables and removes only dead code and formatting. String literals, object properties accessed via dot notation, and exported function names are preserved to maintain compatibility.

Terser applies many optimizations including: variable name mangling, dead code elimination, expression simplification, constant folding, consecutive declaration merging, block removal, unreachable code removal, and function inlining for small functions. These transformations reduce size while maintaining identical runtime behavior.

By default, Terser may remove semicolons where they are not required by JavaScript's automatic semicolon insertion (ASI). Enabling "Preserve Semicolons" forces Terser to keep all semicolons in the output, which is useful if your codebase follows a strict semicolon-style convention or if you want maximum clarity in the minified output.

Yes. Both js-beautify and Terser fully support modern JavaScript syntax including arrow functions, template literals, destructuring, async/await, classes, modules, optional chaining, nullish coalescing, and all other ES2015+ features. No transpilation is needed — the tool works with the syntax as-is.

The tool is designed for standard JavaScript. Terser has limited JSX support but cannot parse TypeScript syntax (type annotations, interfaces, enums). If you need to process TypeScript, compile it to JavaScript first using the TypeScript compiler, then use this tool to beautify or minify the output.

No, never. All JavaScript formatting and minification happen entirely within your browser. js-beautify and Terser run as client-side libraries. No code is transmitted, uploaded, or stored on any server. Disconnect from the internet and the tool still works perfectly.

The tool supports JavaScript input up to 200,000 characters. This covers the vast majority of real-world JavaScript files including large application bundles, library source files, and framework outputs. For significantly larger files, consider splitting them before processing.

Terser typically achieves 40-70% file size reduction depending on the code. Well-formatted code with descriptive variable names and comments will see the highest savings. Already-minified code or code with short names will see smaller reductions. The tool displays exact bytes saved after each minification.

All JavaScript formatting and minification are performed entirely in your browser. No data is uploaded or stored.

Format and minify JavaScript instantly — optimized, clean, and 100% client-side.