JavaScript beautifier for debugging
JS Beautifier restores indentation and line breaks so minified JavaScript becomes easier to inspect. It is helpful for quick review, but it does not recover original source names or comments.
Developer Tools
JS Beautifier
Format JavaScript code with clean indentation.
Use the tool
Use JS Beautifier to make compact JavaScript easier to inspect when debugging scripts, snippets, bundles, and pasted examples.
Dev Workbench
JS Beautifier
Format JavaScript code with clean indentation.
Input
Result
Run the tool to see output.
Lines: 0Chars: 0
Why use JS Beautifier
- Un-minify JavaScript snippets copied from production bundles or third-party embeds.
- Inspect nested functions, objects, arrays, and callbacks while debugging.
- Prepare readable code samples for support tickets, reviews, or documentation.
- Understand what a script does before deciding whether it belongs in a page.
About this tool
Readable code is not original source
Beautified output can reveal structure, function boundaries, object literals, and control flow. Obfuscated or bundled code may still be difficult to understand because naming and module boundaries are lost.
Check before copying
After beautifying JavaScript, run real syntax checks, tests, and security review before reuse. Formatting changes readability, not runtime correctness or trustworthiness.
Example usage
Input
function test(){return true;}Output
function test() {\n return true;\n}Practical guide for JS Beautifier
Best practices
- Use beautified output to inspect structure before debugging or documenting a script.
- Review unknown scripts for network calls, eval, storage access, and injected markup.
- Run linting, tests, or a real parser before committing any edited JavaScript.
Common mistakes
- Assuming beautified code is the same as the original source.
- Trusting third-party JavaScript because it is now easier to read.
- Deploying beautified bundles and increasing page weight unnecessarily.
How this tool works
Step 1
Open JS Beautifier and review the default example input.
Step 2
Paste your own input or upload source data when required.
Step 3
Run JS Beautifier to generate output instantly in the browser.
Step 4
Verify the output using the preview and formatting helpers on the page.
Step 5
Copy the final result and continue with a related tool if needed.
Related tools
Use related links to continue your workflow and keep your output consistent across ToolHarbor pages.
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Popular workflows
FAQ
Can JS Beautifier reverse minification?
It can restore readable spacing and indentation, but it cannot reliably restore original variable names, comments, module files, or source maps.
Does beautifying JavaScript make it safe?
No. You still need to review the logic, source, dependencies, and permissions before running unknown JavaScript.
Should beautified JavaScript be deployed?
Usually no. Use beautified output for review and keep production bundles minified through your normal build process.
What code should I inspect after beautifying?
Look for network calls, DOM changes, eval-style behavior, storage access, event handlers, and unexpected third-party URLs.