Loading…

About Online JavaScript Beautifier

Struggling with minified or messy JavaScript? Our JavaScript Beautifier turns compressed one-liners into readable, well-structured code with a single click. The tool uses the same core component as the JavaScript minifier but defaults to the <strong>Format</strong> action, so you can switch between readable and compact output whenever you need. Everything runs client-side for speed and privacy.

Why Use This JavaScript Beautifier?

  • Reformat messy or minified JavaScript into clean, readable code
  • Prettier-style formatting rules for modern JavaScript syntax
  • Same core component as the JavaScript Minifier, but default action is <strong>Format</strong>
  • Great for debugging packed scripts and third-party snippets
  • One-click copy or download of beautified JS
  • Customizable indentation (spaces/tabs) and line length hints
  • Works in the browser on desktop and mobile
  • 100% client-side processing – your JS never leaves the page

🛠️ How to Beautify JavaScript Code for javascript-beautifier

1

Paste or Upload Your JS

Drop a .js/.mjs file into the editor or paste your JavaScript snippet. The tool is perfect for compressed scripts, inline snippets and tag manager payloads.

2

Choose the Format Action

Because it shares the same component as the JavaScript Minifier, you will see both <strong>Format</strong> and <strong>Minify</strong> actions. For beautifying, keep the action set to Format (the default).

3

Apply Formatting Rules

The code is parsed into an AST and reprinted with consistent indentation, spacing and line breaks while preserving behavior.

4

Inspect, Debug & Export

Use the beautified view to debug or review the code. Then copy from the output editor or download a formatted .js file for local use.

Technical Specifications

Supported Syntax (Formatter Mode)

Focuses on modern JavaScript syntax in a single file.

FeatureSupportNotes
ES2015+ syntax✅ Fulllet/const, arrow functions, async/await, classes, etc.
Modules (import/export)✅ FullStandard ESM syntax in .js/.mjs
Optional chaining / nullish coalescing✅ Full?. and ?? operators
Template literals✅ FullPreserves embedded expressions and string content
Basic JSX✅ PartialWorks when the underlying formatter is configured for JSX-like syntax in .jsx
TypeScript-specific syntax⚠️ Not primary targetBest used with plain JS output from a TS transpiler

Formatting Options (Mapped to Tool UI)

These options are exposed via the editor controls and mapped to the underlying formatter.

OptionValuesDefault
Indent styleSpaces / TabsSpaces
Indent size1–8 spaces when using spaces2 spaces
Line wrapping hint0 (off) to ~120 columns80 characters
End of lineLF (\n) / CRLF (\r\n)LF (\n)
Semicolons / quotes / trailing commasFormatter defaultsConsistent, opinionated style

Performance Benchmarks

Rough performance snapshots in a modern browser on a typical laptop.

File SizeBeautify TimeNotes
5 KB⚡ < 50 msInstant feedback for small snippets
50 KB⚡ < 200 msSmooth interactive editing
250 KB⏳ < 1 sGood for most single-file scripts
1 MB⏳ ~ 2–3 sStill usable; beyond that prefer local tools

CLI Alternatives for Local Workflows

For full projects, run a formatter in your editor, pre-commit hooks, or CI instead of beautifying one file at a time.

Node.js / Cross-platform

Prettier (recommended formatter)

npx prettier --write "src/**/*.js"

Apply consistent formatting to all JavaScript files in your project.

Prettier check mode

npx prettier --check "src/**/*.js"

Use in CI to ensure committed code respects formatting rules.

Common Use Cases

Debugging Minified or Obscure Scripts

  • Reformat packed vendor snippets to understand what they do
  • Inspect tag manager injections or third-party widgets
  • Track down suspicious or broken logic in compressed JS

Code Review & Learning

  • Beautify code pasted from forums or Q&A sites
  • Standardize style before submitting patches
  • Use readable formatting to teach JavaScript concepts

Cleanup Before Refactoring

  • Normalize style in legacy scripts before big changes
  • Spot dead branches or duplicated logic more easily
  • Prepare code for migration into a modern build pipeline

❓ Frequently Asked Questions

Will beautifying JavaScript change how my code runs?

A proper beautifier only changes formatting (whitespace, indentation, line breaks) and not the logic itself. Under normal circumstances, behavior stays identical. If your code relies on very specific whitespace in strings or template literals, always run tests after formatting.

What is the difference between beautifying and minifying?

Beautifying makes code easier to read with consistent formatting. Minifying makes code smaller by stripping whitespace, comments and sometimes performing structural optimizations. This tool exposes both actions through the same component—use Format for readability and Minify for production bundles.

Does this tool support JSX or TypeScript?

The primary target is plain JavaScript. Simple JSX-like syntax may format correctly when the underlying formatter supports it, but for full JSX/TS projects you should run a dedicated formatter (like Prettier) directly in your editor or CI pipeline.

Is my JavaScript code uploaded to a server?

No. Beautification runs entirely in your browser. This makes it suitable for private code snippets, internal tools and quick audits, without sending source code to third-party servers.

How big can my JS file be for comfortable beautifying?

For the best experience, keep individual files under ~1 MB. Larger bundles will still work but local tools and editor integration are usually more efficient.

Additional Resources

ECMA-262 (ECMAScript Language Specification)
Technical specification
MDN: JavaScript Guide
Documentation
Prettier – Opinionated Code Formatter
Documentation

Other Tools