Design Collaborative Code Editor

LinkedIn's "Design Collaborative Code Editor" is a system design interview question focusing on real-time collaboration, often compared to tools like CoderPad or Google Docs for code. It emphasizes backend scalability, real-time syncing across web/mobile clients, and safe code execution.[4][6]

Problem Statement

Design a collaborative code editor that enables multiple users (e.g., 2-3 in interviews) to edit code simultaneously in real-time. Key goals include syncing text changes instantly, executing code securely in isolated environments, retaining session content long-term (e.g., 10 years), and supporting web/mobile access with low latency.[2][6][4]

Functional Requirements

• Real-time text editing with multi-user cursors and conflict resolution (e.g., Operational Transformation or CRDTs).
• Code execution in sandboxed environments supporting multiple languages.
• Session sharing/joining, authentication, and persistence.
• Features like syntax highlighting, autocompletion, and version history.[5][2][4]

Non-Functional Requirements

• Scale to thousands of concurrent sessions with <100ms latency for edits.
• High availability (99.9%+ uptime), secure execution to prevent sandbox escapes.
• Data retention for 10+ years; handle mobile/web clients with offline support.[6][2][4]

Constraints and Examples

No formal input/output examples exist as this is open-ended, but typical scenarios include:

• Example 1: Users A and B join session ID "123"; A types "print('Hello')", B sees it instantly and adds a cursor at line 2.
• Example 2: Execute Python code; output streams to all clients without affecting others.
• Constraints: Max 10 users/session, 1MB code limit, 1000s daily active sessions, bursty interview traffic.[2][4][6]