YouDub WebUI is a full-stack video localization platform that enables users to import videos, transcribe speech via Whisper, translate via OpenAI-compatible APIs, clone voices with VoxCPM2, separate audio with Demucs, align subtitles with Qwen3 Forced Aligner, and export dubbed videos or subtitles. The architecture is plugin-based (Cordis framework) with a Node.js/TypeScript host orchestrating Python subprocesses for ML inference, a Next.js web frontend, and native desktop apps for macOS (Swift) and Windows (C#). The system features a task engine with queuing, cancellation, retry, and partial rerun; a worker protocol using NDJSON over stdin/stdout; and a comprehensive setup service that downloads and verifies model weights. While primarily an application, it includes research-grade model consumption and detailed validation records documenting real-media runs with SHA-256 hashes and human listening feedback. The codebase is actively maintained with recent commits, CI/CD pipelines, and extensive unit tests for contracts, protocols, and permissions.