Umbra

Umbra is an open-source, real time collaborative code execution platform.

Umbra is a browser-based code editor that enables real-time collaboration and code execution. It was built with the following priorities in mind:

• Make spontaneous pair and group programming easy, lightweight, and convenient
• Provide low-latency, automatic conflict resolution in collaborative text editing
• Ensure secure, resilient execution of arbitrary user code

The major components of Umbra's service-oriented architecture are:

1. WebSocket-powered real time collaboration service that handles conflict-free replicated data type (CRDT) transactions and state synchronization between users, and persists sessions through connection loss
2. Node.js with Express back-end server that exposes API endpoints for creating, editing, and deleting code snippets (backed by a scalable PostgreSQL database)
3. Self-hosted, integrated Piston code execution server
4. User interface built with React, TypeScript, and ChakraUI, featuring a customized CodeMirror component integrated with Yjs

You can read more in the Umbra case study, which explores the decisions we made when designing and implementing Umbra.