Worked on the cloudflare/workers-sdk repository to deliver Sandbox SDK preview URLs support and WebSocket routing for Hot Module Replacement (HMR) within the Cloudflare Vite plugin. Using TypeScript and Node.js, implemented logic to ensure WebSocket requests are correctly forwarded while preserving the original request origin, which is essential for maintaining HMR fidelity in development environments. This feature improved the reliability of the dev-server and enhanced the preview testing experience for Cloudflare Workers SDK users. The work focused on full stack development and testing, enabling more stable and efficient sandboxed development workflows without introducing any bug fixes during the period.