JSONToTable
Loading JavaScript Deobfuscator...
Please wait a moment

How to Deobfuscate JavaScript - Step by Step Guide

Step 1

Input Your Obfuscated JavaScript

Let's make your obfuscated JavaScript readable! Need to protect code instead? Try our JavaScript Obfuscator. You have several convenient options:

•
Paste directly: Copy your obfuscated or minified JavaScript and paste it into the input editor
•
Upload a file: Click "Upload" to select an obfuscated .js file from your computer
•
Try the sample: Click "Sample" to see how deobfuscation works

Example: Obfuscated JavaScript Input

Here's obfuscated JavaScript that's hard to read:

function _0x2a4b(_0x1c5d,_0x3e7f){if(_0x1c5d["\x6c\x65\x6e\x67\x74\x68"]<0x3)return![];return _0x3e7f["\x6c\x65\x6e\x67\x74\x68"]>=0x8;}
Step 2

Automatic Deobfuscation & Formatting

The deobfuscator makes your ECMAScript code readable! The tool automatically applies multiple techniques:

•
Beautifies code: Adds proper indentation and line breaks for readability
•
Decodes strings: Converts hex-encoded and base64 strings back to readable text
•
Simplifies structure: Removes unnecessary complexity where possible

Example: Deobfuscated Output

The same code, now deobfuscated and readable:

function _10827(_7261, _15999) {
  if (_7261["length"] < 3) {
    return false;
  }
  return _15999["length"] >= 8;
}
Step 3

Review and Understand the Code

Analyze the deobfuscated code with improved readability:

•
Syntax highlighting: Color-coded output makes code structure clear
•
Line numbers: Easy navigation and reference to specific code sections
•
Proper structure: Indentation shows function nesting and code flow
Step 4

Export Deobfuscated Code

Save your readable JavaScript for analysis or documentation:

•
Copy to clipboard: One-click copying for easy use in your projects
•
Download as file: Save deobfuscated code as a .js file
•
Further beautify: Use with our JavaScript Beautifier for additional formatting

Frequently Asked Questions

What is JavaScript deobfuscation?

JavaScript deobfuscation is the process of converting obfuscated or minified code back into a more readable format. It includes beautifying the code structure, decoding encoded strings, and simplifying complex patterns to make the code easier to understand and analyze.

Can this tool fully recover original variable names?

No, deobfuscation cannot fully recover original variable and function names that were changed during obfuscation. However, it can decode string literals, improve code formatting, and make the logic easier to follow. Original names are permanently lost unless comments or hints remain in the code.

Is it legal to deobfuscate JavaScript code?

Deobfuscating code for learning, debugging your own code, or security research is generally legal. However, reverse engineering proprietary software to steal intellectual property or circumvent licensing may violate terms of service or copyright laws. Always respect software licenses and intellectual property rights.

Will deobfuscated code work the same as obfuscated code?

Yes, deobfuscation only improves readability without changing functionality. The code performs exactly the same operations. However, some obfuscated code includes anti-debugging or anti-tampering checks that may break if the code structure is modified.

Can I deobfuscate heavily obfuscated code?

The tool can handle various levels of obfuscation, including string encoding, minification, and basic transformations. However, heavily obfuscated code with advanced techniques may require multiple passes or manual analysis. The tool provides a good starting point for understanding complex obfuscated JavaScript.

How does this differ from a JavaScript beautifier?

A JavaScript beautifier only formats code structure with proper indentation and spacing, while a deobfuscator goes further by decoding encoded strings (hex, unicode), converting obfuscated number formats, and attempting to simplify intentionally obscured code patterns. For simple minified code, try the JavaScript Beautifier.

Can this deobfuscate code from javascript-obfuscator tool?

Yes, this tool can handle many common patterns from the popular javascript-obfuscator library, including hex-encoded strings, unicode escapes, and basic transformations. However, very aggressive obfuscation with advanced techniques may require additional manual analysis. The tool provides a solid starting point for understanding heavily obfuscated code.

What obfuscation techniques does this tool handle?

The deobfuscator handles hex-encoded strings (\\x notation), unicode escape sequences (\\u notation), hexadecimal number literals (0x prefix), and automatic code beautification. It works well with webpack bundles, production minified code, and basic obfuscation patterns. For more advanced obfuscation like array lookup tables and control flow flattening, multiple passes may be needed.

Is my JavaScript code secure when using this tool?

Yes, completely secure! All deobfuscation processing happens entirely in your browser using client-side JavaScript. Your code never leaves your computer or gets sent to any server, ensuring complete privacy for proprietary or sensitive code. This makes it safe for analyzing commercial software or confidential scripts.

Is the JavaScript deobfuscator completely free?

Yes, totally free with no limitations on file size or usage frequency. No registration required, and you can deobfuscate unlimited JavaScript files. All processing happens in your browser for privacy.

Understanding JavaScript Obfuscation Techniques

JavaScript obfuscation uses various techniques to make code difficult to read and understand. Learning about these methods helps you better deobfuscate and analyze obfuscated code. For more on code obfuscation concepts, see software obfuscation. Here are the most common obfuscation techniques you'll encounter:

String Encoding

One of the most common obfuscation methods. Readable strings are converted into hex-encoded (\\x notation), unicode escape sequences (\\u notation), or base64 encoded values. This tool automatically decodes these patterns back into readable text.

Example:

"\\x68\\x65\\x6c\\x6c\\x6f" → "hello"

Variable Name Mangling

Meaningful variable and function names are replaced with short, cryptic names like _0x2a4b, _0x1c5d, or single letters. While this technique makes code harder to understand, the deobfuscator can still format the code structure properly. Unfortunately, original variable names cannot be recovered.

Example:

calculateTotal → _0x2a4b

Number Obfuscation

Decimal numbers are converted to hexadecimal format (0x prefix), making simple values harder to recognize. The deobfuscator automatically converts these back to readable decimal numbers for easier understanding.

Example:

0x3 → 3, 0x8 → 8, 0xFF → 255

Control Flow Flattening

Linear code execution is transformed into complex switch-case statements or nested conditionals, making the program flow difficult to follow. This advanced technique requires careful manual analysis even after deobfuscation and beautification.

Dead Code Injection

Meaningless code that never executes is inserted throughout the program to increase complexity and confuse readers. While deobfuscation can format this code properly, identifying and removing dead code requires understanding the program logic.

Deobfuscation Best Practices

  • •Start by using this deobfuscator to decode strings and beautify structure
  • •Look for patterns in variable names to understand code organization
  • •Use browser developer tools to debug and step through complex code
  • •For heavily obfuscated code, try the JavaScript Formatter after deobfuscation
  • •Remember that deobfuscation is legal for learning, debugging your own code, and legitimate security research

Related Tools

JavaScript Formatter

Format and beautify JavaScript code online with proper indentation and structure

JavaScript Minifier

Minify and compress JavaScript code online for production deployment and optimization

JavaScript Beautifier

Format and beautify JavaScript code with proper indentation

JavaScript Compressor

Advanced compression with multiple optimization levels

JavaScript Validator

Validate JavaScript syntax and detect errors with detailed reporting

JavaScript Linter

Analyze code quality, detect bugs and enforce best practices