wscat

wscat is a command-line WebSocket client and server, enabling interactive communication with WebSocket endpoints. Current stable version is 6.1.0, released irregularly as part of the websockets ecosystem. It supports both connecting to servers and listening for connections, with features like authentication, SSL/TLS, proxy support, and slash commands for control frames. Unlike browser-based WebSocket tools, wscat is lightweight and runs directly in the terminal with Node.js. Appropriate for testing, debugging, and scripting WebSocket interactions.