JSVeil is a free online JavaScript obfuscator that uses virtual-machine obfuscation to make your code harder to understand, reproduce and tamper with.
Open the website, add your JavaScript and download the protected result. No installation or local build setup is required.
JavaScript VM obfuscation translates protected logic into a custom bytecode format. A generated interpreter executes that bytecode when the resulting JavaScript runs.
This adds a layer between the visible code and the original program logic. Understanding the protected program involves understanding both its bytecode and the virtual machine that executes it.
- Free to use. Obfuscate JavaScript directly at jsveil.com.
- VM-based protection. Protected logic runs as custom bytecode inside a generated virtual machine.
- Fresh output by default. Each obfuscation uses a random seed; choose a custom seed when you need repeatable output.
- Configurable protection. Built-in protection is enabled by default, with additional controls for code structure, runtime restrictions and debugging.
- A practical online editor. Paste code or open a file, inspect the output, then copy or download it. Your custom options are remembered between visits.
- Seven languages. English, Simplified Chinese, Traditional Chinese, German, French, Japanese and Russian.
- Open jsveil.com.
- Paste your JavaScript or open a file.
- Adjust Custom Obfuscation Options if needed.
- Select Obfuscate JavaScript and complete verification.
- Review the result in Output, then choose Copy or Download.
Additional options are off by default, so you can choose the features that fit your project.
| Option | What it does |
|---|---|
| Custom Seed | Use a fixed seed for repeatable output with the same code, options and compiler version. |
| Rename Globals | Rename eligible global identifiers. |
| Bogus Control Flow | Add misleading branches to make the control flow harder to follow. |
| Environment Checks | Restrict execution to supported browser environments. |
| Domain Lock | Limit execution to selected hostnames, including wildcard subdomains. |
| DevTools Detection | Check for open developer tools while the protected code runs. |
| VM Timeout Check | Stop protected code after repeated long execution pauses. |
| Disable Console Output | Suppress console output. |
| Debug Protection | Add debugger traps, with an adjustable trigger interval. |
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