Collaborative Editing: OT and CRDT Approaches

Collaborative editing addresses simultaneous document modifications through two primary approaches: Operational Transformation (OT) and Conflict-free Replicated Data Type (CRDT). OT focuses on operation-based synchronization with server-side transformation logic, while CRDT employs state-based data structures for conflict-free replication. The text compares their architectures, performance characteristics, and use cases in systems like Google Docs and Figma.

OT requires complex server-side logic to transform concurrent operations, ensuring causal consistency but introducing latency challenges at scale. CRDTs offer lower server overhead by maintaining replicated data structures that automatically resolve conflicts through mathematical properties. Both approaches are implemented in open-source libraries like ot.js, yjs, and @atom/teletype-crdt.

Key technical considerations include handling write conflicts, maintaining document state integrity, and optimizing performance for large-scale collaboration. The article also discusses CRDT variants like Treedoc and optimization techniques such as batch operations and garbage collection.