JavaScript Formatter & Beautifier
Format, beautify, and clean up your JavaScript code instantly in a secure, client-side environment.
Formatted output will appear here...About Javascript Formatter
JavaScript Formatter is a free online tool that takes minified, bundled, or inconsistently indented JavaScript and restructures it with proper indentation, line breaks, and spacing so the code becomes readable again. It uses the js-beautify library under the hood, the same engine used by many popular code editors, so the output follows widely accepted style conventions rather than arbitrary rules.
The formatter is useful any time you need to inspect code you did not write yourself: unminifying a vendor bundle to trace a bug, reviewing third-party analytics snippets before adding them to a site, or cleaning up auto-generated code from a build tool. The built-in Minify mode works in the opposite direction — stripping comments, collapsing whitespace, and removing newlines — which is handy for quick compression without a full build pipeline. You can choose between 2-space, 4-space, or tab indentation to match your project style guide.
Every operation runs entirely in your browser. Your JavaScript is never transmitted to a server, logged, or stored, which matters when you are inspecting proprietary application code or unreleased source. There are no file-size limits, no accounts, and no cost.
Key Features
Powered by js-beautify
Uses the same js-beautify engine that ships with VS Code and other editors, so the output matches industry-standard formatting conventions.
Configurable indentation
Switch between 2-space, 4-space, or tab indentation with a single click before formatting to match your team's style guide.
Built-in minifier
The Minify button strips single-line comments, block comments, and excess whitespace in one step — useful for quick size checks without a full build pipeline.
File upload and download
Load a .js, .jsx, or .mjs file directly from disk and save the formatted result back as a .js file, keeping your workflow entirely local.
Handles modern JavaScript syntax
Arrow functions, template literals, destructuring, async/await, classes, and optional chaining are all formatted correctly without errors.
100% client-side processing
All formatting happens in your browser. No code is uploaded to any server, making this safe for proprietary, unreleased, or sensitive application code.
How to Use
Paste Your Code
Copy your minified or messy JavaScript and paste it into the input editor on the left.
Format or Minify
Click "Format" to beautify with proper indentation, or "Minify" to compress for production use.
Copy the Result
Use the copy button to grab your formatted JavaScript, or download it as a .js file.
Example
A minified fetch function is reformatted with 2-space indentation, line breaks after braces, and readable structure — while the logic stays identical.
function fetchUser(id){const url="https://api.example.com/users/"+id;return fetch(url).then(function(r){if(!r.ok){throw new Error("HTTP "+r.status)}return r.json()}).then(function(data){return{id:data.id,name:data.name}}).catch(function(e){console.error(e);return null})}function fetchUser(id) {
const url = "https://api.example.com/users/" + id;
return fetch(url)
.then(function(r) {
if (!r.ok) {
throw new Error("HTTP " + r.status);
}
return r.json();
})
.then(function(data) {
return {
id: data.id,
name: data.name
};
})
.catch(function(e) {
console.error(e);
return null;
});
}Common Use Cases
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Debugging minified production bundles
When a JavaScript error points to line 1, column 47382 of a bundle, paste the minified file here to restore readable structure so you can trace the stack frame to the actual function.
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Auditing third-party scripts
Before adding an analytics tag, chat widget, or payment snippet to a site, format it to inspect what it actually does — one of the few cases where reading someone else's minified code is genuinely necessary.
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Reviewing build-tool output
Webpack, Rollup, and esbuild outputs can be hard to read even with source maps disabled. Format the emitted chunk to verify that tree-shaking removed the right code or that a polyfill was included correctly.
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Matching a team style guide before committing
If a colleague sends a snippet formatted with tabs and you use spaces, paste it here, switch the indent selector, reformat, and paste the result back — faster than running a linter from scratch.
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Quick compression check without a build pipeline
Use the Minify button to estimate how much a small utility function shrinks before wiring it into a full build process, without needing Node.js or a bundler installed.