JavaScript Obfuscator
Free online JavaScript obfuscator to protect your client-side code from casual theft and reverse engineering. Rename identifiers, encode strings, flatten control flow, and add debug protection — all in your browser. Your code is never uploaded.
🛡️ What This Tool Does
A free online JavaScript obfuscator that transforms your readable source code into functionally identical but hard-to-read output. The obfuscation is done locally in your browser using the battle-tested javascript-obfuscator library — the same engine that powers commercial tools. Your source code never leaves your device.
Obfuscation is a standard IP-protection technique used by every major web application to discourage casual code theft and reverse engineering. Variable names are renamed to meaningless hex strings, string literals are moved to encoded lookup arrays, control flow is flattened, dead code is injected, and optional debug protection can block browser devtools inspection.
⚙️ Presets Explained
⚡ Light
- • Identifier renaming
- • Basic string array
- • Compact output
Fast execution, minimal size overhead. Use for performance-critical code.
⚖️ Medium
- • Everything in Light
- • Control flow flattening
- • Dead code injection
- • Self-defending code
- • Base64 string encoding
Recommended default. Balanced protection and performance.
🔒 Strong
- • Everything in Medium
- • Debug protection
- • Console output disabled
- • RC4 string encoding
- • Maximum flattening
Heaviest protection. Runtime can be 2-10x slower.
🎯 Legitimate Use Cases
💼 IP protection
Protect proprietary business logic, algorithms, or pricing rules that ship to the client.
🎮 Browser games
Make it harder for cheaters to find and modify game state variables in the client.
🔐 License checks
Make client-side license validation harder to bypass (note: server-side validation is still required).
📦 Pre-production
Obfuscate bundled output from webpack/Rollup as a final step before deployment.
⚠️ Important — Security Disclaimer
- • Obfuscation is not encryption. Determined attackers can always reverse it given enough time. It raises the cost of reverse engineering, not the possibility.
- • Never use it for security-critical logic. Server-side validation is always required for anything sensitive (auth, payments, license checks).
- • Legitimate use only. Obfuscate code you own or have explicit permission to obfuscate. Do not use this tool for malware, cheats, or to circumvent legal software protections.
- • Test before deploying. Strong presets can slow execution 2-10x and may break code that uses Function.toString(), eval, or dynamic property access.
🔒 Privacy
- ✓ Obfuscation runs entirely in your browser via the
javascript-obfuscatorlibrary - ✓ Your source code is never sent, stored, or logged
- ✓ Only the library itself is loaded from a CDN — your code stays local
- ✓ Works offline after the page first loads
- ✓ No sign-up, no rate limits, no size restrictions
❓ Frequently Asked Questions
What does JavaScript obfuscation do?
It transforms readable JavaScript into functionally identical but hard-to-read code. Variable names become meaningless hex strings, strings are encoded and moved to lookup arrays, control flow is flattened, and debug protection can be added. The output runs exactly the same as the input — just nobody can read it casually.
Is JavaScript obfuscation legal?
Yes. Obfuscation is a standard practice used by every major web application (Google, Facebook, Netflix, Gmail) to protect their client-side code. It is an IP protection technique, not a hacking tool. Only use it on code you own or have permission to obfuscate.
Will my code still work after obfuscation?
Yes, functionally identical. The obfuscator transforms the syntax but preserves the behavior. However, heavier presets (Strong) can slow down execution by 2-10x and may break code that relies on Function.toString(), eval, or strict identifier names. Always test the output before deploying.
Can obfuscated code be reversed?
Yes, with enough effort. Obfuscation is security through obscurity — it raises the cost of reverse engineering from minutes to hours or days, but a determined attacker can always deobfuscate. It protects against casual code theft and automated scrapers, not against targeted reverse engineering.
What is the difference between Light, Medium, and Strong?
Light: identifier renaming and basic string array encoding. Fast execution, minimal size increase. Medium: adds control flow flattening, dead code injection, and self-defending. Balanced protection and performance. Strong: adds debug protection, disables console output, maximum flattening. Best protection but significant runtime cost.
Is my code private?
Yes. Obfuscation runs entirely in your browser using the javascript-obfuscator library. Your source code is never sent to any server, stored, or logged. Close the tab and nothing is retained.
Does it support modern JavaScript (ES6+)?
Yes. All modern JavaScript syntax is supported including arrow functions, classes, async/await, destructuring, spread operators, template literals, and optional chaining.
Should I obfuscate jQuery, React, or other library code?
No. Only obfuscate your own code, not dependencies — libraries are already public and obfuscating them is pointless and increases bundle size. Production bundlers like webpack, Rollup, and esbuild already minify libraries, which is a lightweight form of obfuscation.