Make your JSON data collaborative and version-controlled 🦜

Documentation | Getting Started | Rust Doc

Loro is a CRDTs(Conflict-free Replicated Data Types) library that makes building local-first and collaborative apps easier. You can now use it in Rust, JS (via WASM), and Swift.

Features Provided by CRDTs

• P2P Synchronization
• Automatic Merging
• Local Availability
• Scalability
• Delta Updates

Supported CRDT Algorithms

• 📝 Text Editing with Fugue
• 📙 Rich Text CRDT
• 🌲 Moveable Tree
• 🚗 Moveable List
• 🗺️ Last-Write-Wins Map

Advanced Features in Loro

• 🚀 Fast Document Loading
• ⏱️ Fast Time Travel Through History
• 🏛️ Version Control with Real-Time Collaboration
• 📦 Shallow Snapshot that Works like Git Shallow Clone

In this example, we demonstrate importing an entire Loro codebase into a Loro-powered version controller, preserving the complete Git DAG history while enabling fast version switching.

import { expect, test } from "vitest"; import { LoroDoc, LoroList } from "loro-crdt"; test("sync example", () => { // Sync two docs with two rounds of exchanges // Initialize document A const docA = new LoroDoc(); const listA: LoroList = docA.getList("list"); listA.insert(0, "A"); listA.insert(1, "B"); listA.insert(2, "C"); // Export all updates from docA const bytes: Uint8Array = docA.export({ mode: "update" }); // Simulate sending `bytes` across the network to another peer, B const docB = new LoroDoc(); // Peer B imports the updates from A docB.import(bytes); // B's state matches A's state expect(docB.toJSON()).toStrictEqual({ list: ["A", "B", "C"], }); // Get the current version of docB const version = docB.oplogVersion(); // Simulate editing at B: delete item 'B' const listB: LoroList = docB.getList("list"); listB.delete(1, 1); // Export the updates from B since the last sync point const bytesB: Uint8Array = docB.export({ mode: "update", from: version }); // Simulate sending `bytesB` back across the network to A // A imports the updates from B docA.import(bytesB); // A has the same state as B expect(docA.toJSON()).toStrictEqual({ list: ["A", "C"], }); });

You can use the Loro Inspector to inspect the state and history of a Loro document.

You can find bindings for other programming languages in loro-ffi.

• Loro 1.0
• Movable tree CRDTs and Loro's implementation
• Introduction to Loro's Rich Text CRDT
• Loro: Reimagine State Management with CRDTs

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

• Diamond-types: The Event Graph Walker (Eg-walker) 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 work.
• Matthew Weidner: His work on the Fugue algorithm has been invaluable, enhancing our text editing capabilities.
• Martin Kleppmann: His work on CRDTs has significantly influenced our comprehension of the field.