JavaScriptVM Obfuscation

There are numerous reasons to protect your code: prevent anyone from simply copy/pasting your work (especially important for client-side projects like HTML5 games), remove comments and whitespace to make code faster to load and harder to understand, and protect work that hasn't been paid for yet so you can show clients without giving them the source code.

VM (Virtual Machine) obfuscation transforms your JavaScript code into custom bytecode that runs on an embedded interpreter. Unlike standard obfuscation which still produces readable JavaScript, VM obfuscation completely hides your original code structure. Static analysis tools cannot understand the logic without first reverse-engineering the entire virtual machine. Learn more in our VM obfuscation guide.

No obfuscation is 100% foolproof since JavaScript must ultimately run in the browser. However, there's a massive difference between protection levels. VM obfuscation offers the strongest protection: an attacker must fully reverse-engineer the custom virtual machine, understand its instruction set, trace bytecode execution, and manually reconstruct the original logic — a process that can take weeks or months of dedicated effort. Standard obfuscation is much easier to defeat: it can often be partially reversed using automated tools and beautifiers, with a skilled attacker potentially restoring readable code in hours.

No. There is no existing deobfuscator for VM-obfuscated JavaScript code, and it's unlikely one will ever be created in the upcoming years. Unlike standard obfuscation where patterns can be recognized and reversed, VM obfuscation compiles code into custom bytecode with a unique virtual machine. Each obfuscation produces different bytecode structures, making automated deobfuscation an extremely complex task. A reverse engineer would need to manually analyze the specific VM implementation, understand its instruction set, and trace through bytecode execution — a process requiring significant expertise and potentially weeks or months of work for complex code.

The obfuscator introduces new code to protect against debugging and reverse-engineering. Strings are converted to hexadecimal, and with VM obfuscation, an entire virtual machine interpreter is bundled with your bytecode. Don't worry too much about size — the obfuscated code compresses extremely well with GZIP, which most servers enable by default.

Any obfuscation will have some impact on performance. Standard obfuscation has minimal overhead. VM obfuscation has more impact: low preset ~3.5x slower, medium ~4x, high ~4.5-5x. You can fine-tune the balance by adjusting options or selectively applying VM obfuscation only to sensitive code sections. See our best practices guide for optimization tips.

No, it's not recommended and in some cases it will break the code (especially if you enable self-defending). You can run your code through a minifier before obfuscation to remove dead code and do other optimizations, though.

No. The source is processed entirely in memory and immediately returned as obfuscated output. Nothing is saved to disk or retained after processing. Your code remains yours alone.

No, it's impossible to revert the obfuscated code back to your original code, so keep the original safe.

Yes. You can select "Node" as the target in the obfuscation options to optimize the output for Node.js environments.

We support ES2015 (ES6) and all modern JavaScript features including ES2022+ syntax, private class fields, async/await, optional chaining, and more. We only support pure JavaScript files — HTML files containing inline JavaScript and JSX are not supported. TypeScript and JSX must be compiled to JavaScript before obfuscation.

Check out our pricing plans for VM protection, or try the free online playground for standard obfuscation. Read the getting started guide for a complete walkthrough.