JavaScript Deobfuscator

What is JavaScript DeObfuscator?

JavaScript DeObfuscator turns scrambled, hard-to-read JavaScript code back into something you can actually understand. Developers often obfuscate their code to protect it or make it smaller, but this makes debugging and learning from it nearly impossible. This tool reverses that process so you can see what the code really does.

Why Would You Need to Deobfuscate JavaScript?

There are many reasons you might need to read obfuscated JavaScript:

• Security analysis: Check if a script from an unknown source contains malicious code before running it on your website
• Debugging issues: Figure out why a third-party script is causing errors when you only have the minified version
• Learning purposes: Understand how a particular JavaScript effect or feature works by studying the original code
• Legacy code maintenance: Work with old scripts where the original source files have been lost
• Browser extension review: Examine what a browser extension actually does with your data

How to Deobfuscate JavaScript - Step by Step

1. Paste or upload your code: Copy your obfuscated JavaScript into the text box, or click Upload to load a .js file directly
2. Choose your options: Select which deobfuscation methods to apply. Leave "Auto-detect" on if you are not sure what type of obfuscation was used
3. Click DeObfuscate: The tool will process your code and apply the selected methods. Multi-pass mode runs multiple rounds for heavily obfuscated code
4. Review the results: Check the output panel to see the cleaned-up code. The tool shows which obfuscation types were detected
5. Copy or download: Use the Copy button to grab the code, or Download to save it as a .js file

Key Features

• Multiple deobfuscation methods: Handles Packer, Base64, Hex encoding, Unicode escapes, Array-based obfuscation, and more
• Auto-detection: Automatically identifies which obfuscation techniques were used in your code
• Multi-pass processing: Runs multiple rounds to handle layered obfuscation where techniques are stacked on top of each other
• Code beautifier: Formats the output with proper indentation so it is easy to read
• File upload support: Load JavaScript files directly instead of copying and pasting
• Detect Only mode: See what obfuscation types are present without changing the code
• Beautify Only mode: Just format the code without attempting to deobfuscate

Supported Obfuscation Types

• Dean Edwards Packer: A popular JavaScript compression tool that creates eval-based packed code
• Base64 encoding: Strings hidden as Base64-encoded values
• Hex escape sequences: Characters written as \x41 instead of "A"
• Unicode escapes: Characters written as \u0041 instead of "A"
• Array-based obfuscation: Strings stored in arrays and accessed by index
• String concatenation: Simple strings split into many parts and joined together
• JSFuck: Code written using only []()!+ characters

Tips for Best Results

• Start with Auto-detect enabled to let the tool figure out what methods to use
• For heavily obfuscated code, enable Multi-pass and set max passes to 5 or higher
• Use Detect Only first if you want to see what you are dealing with before processing
• If results look incomplete, try enabling all deobfuscation methods manually
• Some obfuscation cannot be fully reversed, but the output should still be more readable

Frequently Asked Questions

Can this tool deobfuscate any JavaScript code?

This tool handles the most common obfuscation techniques. However, some heavily customized or proprietary obfuscation methods may not be fully reversible. The tool will still make the code more readable in most cases.

Is my code safe? Do you store it?

Your code is processed in your browser and on our server only during the deobfuscation process. We do not store or log any code you submit.

What is the difference between Deobfuscate and Beautify?

Beautify only reformats the code with proper spacing and indentation. Deobfuscate actually transforms the code to reverse encoding and obfuscation techniques, making the logic visible again.

Why does my code still look messy after deobfuscation?

Variable names that were changed during obfuscation cannot be recovered - we do not know what the original names were. The tool focuses on making the code structure and logic readable, not restoring original variable names.

Can I use this for minified code?

Yes! Use the Beautify Only option to format minified code. If the code is both minified and obfuscated, run the full deobfuscation first.