JS 圧縮・保護ツール

このツールについて

JavaScript code protection covers a spectrum of techniques: minification (removing whitespace and comments to reduce file size), obfuscation (renaming variables and restructuring code to make it harder to read), packing (wrapping code in a self-decoding bundle), and encryption (using a password-based cipher so the content cannot be read without the key). This tool offers all four modes for free, directly in your browser, as a lightweight alternative to paid commercial obfuscators like Jscrambler for quick one-off protection needs. Understanding their security levels is critical: minification, obfuscation, and packing do not prevent a determined developer from reading your code. Real protection—where the code is unreadable without a secret—requires the AES-256-GCM Encrypt mode.

使い方

1. 1Choose a mode: Minify, Obfuscate, Pack, or Encrypt.
2. 2Paste your JavaScript into the input field.
3. 3For Encrypt mode: enter a password — it is required to decrypt the output later.
4. 4Click the action button to process, then copy the result with the "Copy" button.

よくある質問 (FAQ)

What is the difference between Minify, Obfuscate, and Pack?

Minify removes whitespace and comments—the code is shorter but still readable. Obfuscate renames variables to cryptic names—the code is very hard to understand. Pack wraps the code in a self-running decoder—an extra layer of obscurity. None of these prevent a motivated developer from reversing the output.

What does the Encrypt mode do?

Encrypt uses AES-256-GCM with PBKDF2 key derivation (150,000 iterations) to encrypt your code with a password. The output is a Base64 ciphertext blob that is completely unreadable without the password. The password is never stored or transmitted—if you lose it, the data cannot be recovered.

Can I protect my JavaScript so nobody can copy it?

Not fully. Any JavaScript that runs in a browser must be downloaded to that browser, where it can be inspected with developer tools. Minification and obfuscation raise the effort required, but server-side execution (API routes) is the only way to keep logic genuinely private.

Why does minification sometimes break code?

Regex-based minifiers can fail on edge cases: strings that contain comment-like patterns (e.g. "https://..."), certain template literals, or ASI (Automatic Semicolon Insertion) edge cases. For production, use a parser-based tool like Terser, which understands the JavaScript AST and cannot produce syntactically invalid output.

Is this a free alternative to Jscrambler or other commercial obfuscators?

For quick, one-off protection needs, yes—minify, obfuscate, pack, and AES-256-GCM encrypt are all free and run entirely in your browser. Commercial tools like Jscrambler add more advanced, harder-to-reverse transformations (control-flow flattening, anti-debugging, polymorphic code) intended for production-grade, ongoing protection of commercial applications—consider one of those if you need protection against serious reverse-engineering attempts.