JavaScript Obfuscator

Protect your JavaScript code from reverse engineering. All processing happens in your browser — your code never leaves your device.

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Important Limitations

  • · Obfuscation ≠ encryption. A determined reverse engineer can still deobfuscate your code.
  • · Control flow flattening and dead code injection significantly increase file size and can slow execution.
  • · For sensitive secrets, never put them in client-side JavaScript — obfuscated or not.

What each option does

  • · Rename Variables — replaces readable names like userName with _0x1a2b3c.
  • · String Encryption — moves strings into an encoded lookup array, decoded at runtime.
  • · Control Flow Flattening — converts linear code into a state-machine loop to obscure logic.
  • · Dead Code Injection — adds random unreachable code blocks to confuse analysis tools.

Frequently Asked Questions

Does obfuscated code still work normally?

Yes — obfuscated code is semantically identical to the original. It runs exactly the same way in the browser, just in a form that is much harder for humans to read and understand.

Is my code sent to a server?

No. All obfuscation happens entirely in your browser using the javascript-obfuscator library. Your code never leaves your device.

Why does the obfuscated file get larger?

Obfuscation adds overhead — string arrays, decoder functions, and (optionally) dead code. Rename Variables alone adds minimal overhead; enabling Control Flow Flattening and Dead Code Injection can double or triple the file size.

Can I obfuscate minified code?

Yes, but it's best to obfuscate first, then minify (or let the obfuscator's compact mode handle it). Applying obfuscation to already-minified code can sometimes cause issues with variable name collisions.

About JavaScript Obfuscator

The JavaScript Obfuscator transforms readable JS source code into a functionally equivalent but highly unreadable form, making it significantly harder for others to reverse engineer, copy, or tamper with your code — all without leaving your browser.

  • Variable and function renaming with hexadecimal identifiers
  • String array encoding with Base64 to hide literal values
  • Control flow flattening to obscure program logic
  • Dead code injection to confuse static analysis tools
  • Size comparison between original and obfuscated output
  • 100% client-side — your source code never leaves your device

How to Obfuscate JavaScript Online

  1. 1

    Paste your JavaScript

    Paste your JS source into the left editor. A sample script is pre-loaded so you can try it immediately.

  2. 2

    Choose your obfuscation options

    Click "Obfuscation Options" to toggle Rename Variables, String Encryption, Control Flow Flattening, and Dead Code Injection. Higher protection means a larger file.

  3. 3

    Click Obfuscate

    Hit the "Obfuscate" button. The obfuscated code appears in the right panel along with a size comparison showing how much overhead was added.

  4. 4

    Copy and deploy

    Click "Copy" to copy the obfuscated output to your clipboard, then replace your original file in your project.

Tip: For the best balance of protection and performance, enable Rename Variables and String Encryption, but leave Control Flow Flattening off unless you need maximum obfuscation — it can significantly slow down execution.

Common Use Cases

Protecting Proprietary Logic

  • • Hide business algorithms in client-side JS
  • • Protect licensing and activation logic
  • • Obscure API key usage patterns in browser code

SaaS & Web Apps

  • • Protect JavaScript widget embed code
  • • Obfuscate tracking and analytics scripts
  • • Harden client-side form validation logic

Game Development

  • • Obfuscate browser game scoring logic
  • • Protect game engine initialisation code
  • • Make cheat-engine analysis more difficult

Browser Extensions

  • • Protect content scripts before publishing
  • • Obfuscate background service worker logic
  • • Add an extra barrier against forking

Freelance & Agencies

  • • Protect delivered client-side code from copying
  • • Obfuscate custom scripts before handoff
  • • Prevent unauthorised redistribution

Security Research

  • • Study obfuscation techniques hands-on
  • • Compare output across different option combos
  • • Understand how real-world malware uses obfuscation

More Questions About JavaScript Obfuscation

What is JavaScript obfuscation?

JavaScript obfuscation is the process of transforming readable source code into a functionally identical but deliberately difficult-to-understand form. It uses techniques like identifier renaming, string encoding, and control flow restructuring to deter reverse engineering.

What is the difference between obfuscation and minification?

Minification removes whitespace and shortens names purely to reduce file size — it is not a security measure and is easily reversed. Obfuscation actively transforms the code structure to resist human analysis. For production use, you typically minify after obfuscating.

Can obfuscated JavaScript be deobfuscated?

Yes. With enough effort, any obfuscated JavaScript can be deobfuscated — since the browser must be able to execute it, the logic is always recoverable. Obfuscation raises the cost and skill required for reverse engineering, but it is not a substitute for proper server-side security.

Will obfuscated code affect website performance?

Rename Variables and String Encryption add negligible runtime overhead. Control Flow Flattening can slow execution by 1.5–2× due to the state-machine loop it creates. Dead Code Injection increases parse time proportionally to the amount of code injected.

Does this tool support TypeScript or ES modules?

This tool obfuscates plain JavaScript only. Compile your TypeScript to JS first using tsc or your bundler, then paste the compiled output here. ES module syntax (import/export) is supported.

Should I obfuscate before or after bundling?

Obfuscate after bundling — apply it to the final bundle so that all modules are already merged. This gives the obfuscator more context for renaming and produces a single protected output file.

Is my source code safe to paste here?

Yes. All obfuscation runs entirely in your browser using the javascript-obfuscator library. Your source code is never transmitted to any server, stored, or logged. You can safely paste proprietary code.