Design a Collaborative Text Editor

Requirements

• •Allow multiple users to simultaneously edit a shared document with their changes merged conflict-free
• •Show real-time cursor positions and user presence indicators
• •Persist the full operation history to reconstruct the document at any past point in time
• •Handle offline edits: buffer operations locally and sync on reconnect without conflicts
• •Support undo/redo per user without affecting other collaborators edits

Non-Functional Requirements

• •Operation broadcast latency < 100ms to all active collaborators
• •Support 100 simultaneous editors per document
• •Document state converges within 500ms after all offline edits are submitted
• •Full edit history retained for 1 year

Constraints

• •Document type: plain text (no rich formatting in v1)
• •Multiple users can edit the same document simultaneously
• •Users may go offline and reconnect with buffered local edits

Evaluation Criteria