FingerprintJS is a client-side browser fingerprinting library written in TypeScript. It collects over 30 entropy signals (canvas, audio, fonts, WebGL, etc.) from the browser environment and hashes them into a stable visitor identifier. The library operates in two phases: a load phase where entropy sources are prepared asynchronously, and a get phase where values are collected and combined. It includes stabilization logic for browsers that apply anti-fingerprinting measures (e.g., Safari 17, Firefox 120+) and provides a confidence score for the identifier. The architecture is modular: each entropy source is a separate function with a consistent interface, the agent orchestrates collection, and the hashing uses a custom MurmurHash3 x64 128-bit implementation. The library has no runtime dependencies and is tree-shakable. It is used for fraud detection and visitor identification without cookies.
CloakBrowser is a commercial stealth browser automation library that wraps Playwright (Python, JavaScript, .NET) with a custom patched Chromium binary. Its core purpose is to evade bot detection by spoofing browser fingerprints, providing human-like interaction (Bezier mouse moves, realistic typing with typos, smooth scrolling), and managing licensed binary downloads with cryptographic verification. The architecture is a multi-language SDK sharing identical logic across Python, TypeScript, and C#, with a common human interaction engine, proxy/GeoIP integration, and license enforcement via denial files and server validation. Key entry points are the `launch()` and `humanize()` APIs, CLI diagnostics (`info`, `login`, `install`), and the `cloakserve` CDP multiplexer. External dependencies include Playwright/Puppeteer, MaxMind GeoLite2 database, Ed25519 signature verification (BouncyCastle), and a license validation server. The codebase demonstrates high engineering discipline with extensive cross-language parity tests and security-conscious binary distribution, but carries drift risks from triple-language duplication and reliance on Playwright internal APIs.