WelsonJS is a Windows-centric JavaScript runtime and automation framework designed for industrial, security-sensitive, and constrained environments where modern runtimes or build tools cannot be assumed. Built on top of native Windows scripting technologies and extended with carefully designed polyfills and native bridges, WelsonJS enables developers to write reliable, auditable, and portable JavaScript automation logic that runs consistently across a wide range of Windows versions—from legacy systems such as Windows 2000/XP to modern Windows 10/11. WelsonJS focuses on deterministic execution, minimal dependencies, and operational transparency, making it suitable for environments such as: * Industrial control systems (ICS/SCADA) * Security testing and cyber-range simulations * Government or enterprise networks with strict software installation policies * Air-gapped or offline systems * Legacy Windows infrastructures that must remain operational The framework provides: * A lightweight JavaScript execution environment without Node.js or modern browsers * Native access to Windows system components (filesystem, networking, processes, COM objects) * Script-based extensibility without build pipelines or package managers * Structured logging, tracing, and error handling for auditability * Optional integration points for cryptography, compression, networking, and automation workflows WelsonJS is developed as an open-source project under the Catswords OSS ecosystem and is intended for research, education, security validation, and industrial automation use cases, rather than consumer-oriented application development. By prioritizing compatibility, control, and survivability under constraints, WelsonJS enables developers to accomplish critical automation and analysis tasks even in adverse or highly restricted environments.