4.2 Design a Collaborative Document Editor
Design a Collaborative Document Editor
Real-time collaborative editing is a complex feature that allows multiple users to simultaneously modify the same document. This problem explores the design of such a system, similar to Google Docs or Notion, focusing on distributed systems, conflict resolution, real-time communication, and storage design.
Functional Requirements
- Multiple users must be able to simultaneously edit the same document in real time.
- Changes made by one user should be visible to other users within 1-2 seconds.
- The system must gracefully resolve conflicts when two users edit the same section concurrently.
- Users need to be able to browse and restore previous versions of a document.
- The system should provide presence awareness, showing who else is in the document, their cursor positions, and text selections.
- Users must be able to make changes without an internet connection and sync those changes when reconnected.
Non-Functional Requirements
- The system must support up to 100 concurrent editors per document.
- Edits should appear on other users' screens with low latency, ideally under 500ms.
- The system must ensure strong eventual consistency, meaning all users will eventually converge to the same document state, even if they temporarily see different states.
- There must be no data loss; every keystroke must be durably stored.
Scale Expectations
- The system should handle a peak of 80 million operations per minute. Each operation is small (50-200 bytes), making the system operation-heavy but bandwidth-light.
- Total document storage is estimated at 25 TB, across 500 million documents, with an average document size of 50 KB.
AI interview prep
Core dilemma
Reconciling concurrent, distributed edits into a single, consistent document state in real-time, while maintaining low latency, ensuring no data loss, and scaling to millions of operations per minute.
3 tradeoffs and 3 stress tests locked
Interview prep
Unlock the interviewer X-Ray rubric, tradeoff matrix, stress tests, clarifying questions, and key concepts.
4.2 Design a Collaborative Document Editor
Design a Collaborative Document Editor
Real-time collaborative editing is a complex feature that allows multiple users to simultaneously modify the same document. This problem explores the design of such a system, similar to Google Docs or Notion, focusing on distributed systems, conflict resolution, real-time communication, and storage design.
Functional Requirements
- Multiple users must be able to simultaneously edit the same document in real time.
- Changes made by one user should be visible to other users within 1-2 seconds.
- The system must gracefully resolve conflicts when two users edit the same section concurrently.
- Users need to be able to browse and restore previous versions of a document.
- The system should provide presence awareness, showing who else is in the document, their cursor positions, and text selections.
- Users must be able to make changes without an internet connection and sync those changes when reconnected.
Non-Functional Requirements
- The system must support up to 100 concurrent editors per document.
- Edits should appear on other users' screens with low latency, ideally under 500ms.
- The system must ensure strong eventual consistency, meaning all users will eventually converge to the same document state, even if they temporarily see different states.
- There must be no data loss; every keystroke must be durably stored.
Scale Expectations
- The system should handle a peak of 80 million operations per minute. Each operation is small (50-200 bytes), making the system operation-heavy but bandwidth-light.
- Total document storage is estimated at 25 TB, across 500 million documents, with an average document size of 50 KB.