Softonic

JavaScript Obfuscator

Step 1 / 2
Mode
Next

Obfuscation raises the cost of reading your JavaScript source, not absolutely (no front-end obfuscation is bulletproof) but enough to discourage casual inspection and slow down automated scraping. This tool applies string-array encoding, identifier mangling, control-flow flattening and optional dead-code injection, with each option selectable depending on how aggressive you want to be.

How to obfuscate JavaScript

  1. 1

    Paste the source

    Any valid JS. If it relies on specific global property names from a host page, set those as reserved.

  2. 2

    Pick techniques

    String encoding (hex / base64), identifier mangling, control-flow flattening, dead-code injection, self-defending wrapper.

  3. 3

    Pick the target profile

    Browser (ES5-safe, no Node APIs), Node.js (allows `require`, `Buffer`), or low (mostly minify).

  4. 4

    Obfuscate

    The tool outputs the transformed code with a size delta. Aggressive settings can make the output 3-5x larger than the source.

Techniques and what they cost you

Technique Raises attacker effort Runtime cost Size cost
Variable renaming Low Negligible Smaller (minify side effect)
String array encoding Medium Tiny (one lookup per string) +10-30%
Control-flow flattening High Measurable (~2-5%) +50-150%
Dead-code injection Low (security theatre) Small +20-50%
Self-defending wrapper Medium One-time check +5-10%
Debug protection Medium (detects DevTools) One-time check +5%
VM / virtualization (premium) Very high Large (5-20x) +300-500%

What obfuscation cannot protect

  • Secrets. Any constant in your front-end source is readable given enough time. API keys, auth secrets, pricing logic, never rely on obfuscation to hide these. Move them server-side.
  • Algorithms with an observable output. If the browser can run it, an attacker with a debugger can observe every input and output. Obfuscation slows that down; it does not stop it.
  • Automated scraping at scale. Anti-scraping depends on behavioural detection (fingerprinting, rate limits, CAPTCHA), not on source obfuscation.

When obfuscation is worth it

  • Anti-tampering on embedded SDKs (licensing, ad SDKs, game clients).
  • Raising the cost for low-effort copy-paste of a competing implementation.
  • Making automated script classification harder for broad-spectrum scrapers.

When it is counter-productive

  • You have a bundler already. Webpack + Terser in production mode already minifies and mangles locals. Adding a second obfuscation pass buys you little and inflates bundle size.
  • You are optimizing for first-paint / Core Web Vitals. Aggressive obfuscation triples the bundle; that hurts FCP and LCP.
  • You have to debug production. Heavy obfuscation makes Sentry stack traces nearly useless without a matching source map, and shipping the source map defeats the obfuscation.

Common mistakes

  • Treating obfuscation as equivalent to encryption. It is not, it is a speed bump.
  • Shipping the source map alongside the obfuscated bundle to production. That completely neutralizes the obfuscation.
  • Obfuscating third-party libraries you already loaded from a CDN. You get the size penalty without any gain.

Frequently Asked Questions

No. Obfuscation is a speed bump, not a lock. A determined analyst with a debugger will recover the logic. It raises the cost enough to deter casual inspection and most automated scrapers, but it is not security.

If you access properties dynamically (obj["field_name"], Object.keys(obj)) or rely on specific function / class names for the host page, add those to the reserved list. Without that, property renaming can break external integrations.

Keep the original source. The obfuscator is a one-way transform; you cannot exactly recover the original from the obfuscated output, only a readable approximation.

Light obfuscation adds ~10-30%. Control-flow flattening plus string arrays adds 50-150%. The heaviest settings can triple the size. Check the output size counter before shipping.

Related Tools

ASCII Table Reference

Full ASCII table from 0 to 127 with decimal, hex, octal, binary, standard names and HTML numeric-reference notation, including NUL, LF and DEL.

Color Palette Generator

Generate monochromatic, analogous, complementary, triadic or tetradic color palettes from a base HEX color and export copy-ready CSS variables.

HTML Character Reference

Searchable list of HTML entities, their named and numeric codes, and a one-click copy for special characters and symbols.

FPS Counter

Measure browser FPS with requestAnimationFrame, smoothing, min/max frame rate, warnings and an optional graph. Runs locally with no upload or API.

HEX Color Picker

Pick or enter a HEX colour and get RGB, HSL, approximate CMYK, relative luminance and contrast ratios against white and black.

JSON Formatter

Paste JSON to pretty-print with 2 or 4 spaces, minify it to compact output, or run a quick syntax check before copying the result.

Tool available in other languages