Loro
Sync state easily with CRDTs

Notice: The current API and encoding schema of Loro are subject to change. It is not recommended for use in production environments at this time.

Loro is a CRDTs(Conflict-free Replicated Data Types) library that allows you to persist and sync state easily. It is designed to make building local-first apps easier.

What are CRDTs? Conflict-free Replicated Data Types (CRDTs) are data structures that enable automatic conflict resolution. It allows users to make changes together, in real-time or asynchronously, without conflicting or relying on a central server.

Features

Supported CRDT Algorithms

• Common Data Structures: Support for List for ordered collections, LWW(Last Write Win) Map for key-value pairs, Tree for hierarchical data, and Text for rich text manipulation, enabling various applications.
• Text Editing with Fugue: Loro integrates Fugue, a CRDT algorithm designed to minimize interleaving anomalies in concurrent text editing.
• Peritext-like Rich Text CRDT: Drawing inspiration from Peritext, Loro manages rich text CRDTs that excel at merging concurrent rich text style edits, maintaining the original intent of users input as much as possible. Details on this will be explored further in an upcoming blog post.
• Moveable Tree: For applications requiring directory-like data manipulation, Loro utilizes the algorithm from A Highly-Available Move Operation for Replicated Trees, which simplifies the process of moving hierarchical data structures.

Special Powers of Loro

• Preserve Editing History
  • With Loro, you can track changes effortlessly as it records the editing history with low overhead.
  • This feature is essential for audit trails, undo/redo functionality, and understanding the evolution of your data over time.
• Time Travel Through History
  • It allows users to compare and merge manually when needed, although CRDTs typically resolve conflicts well.

Features Provided by CRDTs

• High Performance
• Decentralized Synchronization: Loro allows your app's state can be synced via p2p connections.
• Automatic Merging: Say goodbye to merge conflicts. Loro guarantees eventual consistency, automating the merging of concurrent changes.
• Local Availability: Data is persistently available on users' devices, ensuring offline functionality and real-time responsiveness.
• Scalability: Effortlessly scale your application horizontally thanks to the inherently distributed nature of CRDTs.
• Delta Updates: Loro has out-of-the-box support for delta updates.

Credits

Loro draws inspiration from the innovative work of the following projects and individuals:

• Ink & Switch: The principles of Local-first Software have greatly influenced this project. The Peritext project has also shaped our approach to rich text CRDTs.
• Diamond-types: The ingenious OT-like merging algorithm from @josephg has been adapted to reduce the computation and space usage of CRDTs.
• Automerge: Their use of columnar encoding for CRDTs has informed our strategies for efficient data encoding.
• Yjs: We have incorporated a similar algorithm for effectively merging collaborative editing operations, thanks to their pioneering contributions.
• Matthew Weidner: His work on the Fugue algorithm has been invaluable, enhancing our text editing capabilities.