Prosopo is a privacy-focused, self-hosted CAPTCHA alternative that provides multiple challenge types—image selection, puzzle (image jigsaw), proof-of-work, and frictionless (behavioral bot detection). The system comprises an Express-based provider API (with MongoDB and Redis for persistence and caching), a CLI for administrative tasks, client-side embeddable widgets (vanilla JS bundle, React/Angular/Vue/Svelte wrappers), and a suite of supporting libraries for cryptography, locale, datasets, and native Rust modules (JA4 TLS fingerprinting, Merkle tree acceleration, puzzle rendering). Bot detection is multi-layered: client-side behavioral data (mouse/keyboard/touch events, SIMD readings) is collected and server-side scored, combined with JA4 TLS fingerprint analysis, IP reputation (ipapi.is + MaxMind), DNS asymmetry detection, spam email heuristics, and custom decision machines per site key. The architecture is a monorepo with ~70 workspaces, leveraging Vite for bundling, Vitest for unit/integration tests, and Cypress for E2E visual regression testing. The provider enforces access policies (allow/block/restrict) via a Redis-backed rules engine and maintains usage counters for rate limiting. Asset sealing (AES-256-GCM) protects image CDN URLs, and puzzle difficulty is sampled with a CSPRNG-stratified ladder to frustrate solver calibration.
The hCaptcha Vue Component Library provides Vue 2 and Vue 3 components for integrating hCaptcha into Vue applications. The library consists of two packages (@hcaptcha/vue-hcaptcha for Vue 2 and @hcaptcha/vue3-hcaptcha for Vue 3) built from a shared Vue component source. The component handles loading the hCaptcha API script, rendering the widget, and emitting events for verification, expiration, and other hCaptcha callbacks. It also provides methods to programmatically execute and reset the challenge. A notable utility in the library is the script loader (hcaptcha-script.js) which ensures the hCaptcha API is loaded only once per page using a promise-based pattern. This utility is framework-agnostic and could be reused in other projects requiring singleton script loading. The repository is set up as a monorepo using Lerna, with separate build processes for Vue 2 (using Vue CLI) and Vue 3 (using Vite). While the component itself is well-maintained and functional, the build toolchain shows signs of technical drift with outdated dependencies (e.g., Vue CLI 3, Vite 2, Jest 26). The project is actively maintained with CI pipelines for building, testing, and releasing new versions.