Chromie: WebSocket Proxy for Headless Chrome Sessions

Chromie is a lightweight WebSocket proxy server written in Crystal (using the Kemal web framework) that acts as a pool manager for headless Chrome browser instances. When a client connects to its /browser WebSocket endpoint, Chromie dynamically spawns a new Chrome process on an available port within a configurable range (defaulting to 9222–9322), then transparently proxies bidirectional WebSocket traffic between the client and that Chrome instance using the Chrome DevTools Protocol (CDP). It manages concurrent browser sessions safely with mutex-locked port allocation to prevent conflicts, cleans up Chrome processes on disconnect, and exposes a /health endpoint for uptime monitoring. It's essentially a self-contained headless Chrome session broker that lets multiple clients share a pool of on-demand browser instances without any manual process management.