synckit-core

High-performance sync engine for local-first applications. Powers the SyncKit collaboration SDK.

What is this?

synckit-core is the Rust/WASM core that implements SyncKit's CRDTs:

• Fugue CRDT - Collaborative text editing with minimal interleaving
• Peritext - Rich text formatting with conflict resolution
• LWW - Last-write-wins for document metadata
• PN-Counter - Increment/decrement counter
• OR-Set - Add/remove set operations

Built for JavaScript consumption via WASM, but usable as a native Rust library.

Installation

[dependencies]
synckit-core = "0.2.0"

Usage

Document Operations

use synckit_core::{Document, Operation};

// Create a document
let mut doc = Document::new("client-1");

// Insert text
doc.insert(0, "Hello");
doc.insert(5, " World");

// Get text
assert_eq!(doc.text(), "Hello World");

// Generate operations for sync
let ops = doc.pending_operations();

Text CRDT (Fugue)

use synckit_core::text::FugueReplica;

let mut replica = FugueReplica::new("client-1");

// Insert text
replica.insert(0, "Hello");

// Apply remote operations
replica.apply_operation(remote_op);

// Convert to string
let text = replica.to_string();

Features

• default - Core CRDTs with minimal dependencies
• text-crdt - Fugue text CRDT with rope data structure
• full - All CRDTs, rich text (Peritext), and binary protocol
• wasm - WASM bindings for JavaScript

See Cargo.toml for all available features.

Architecture

This crate is designed for:

• WASM compilation - Small bundle size with aggressive optimization
• Zero unsafe code - Pure safe Rust
• Deterministic behavior - Same operations produce same results

Optimized profiles:

• release - Standard optimization
• wasm-release - Size-optimized for WASM (opt-level = "z")

Documentation

• Main Repository
• JavaScript SDK
• API Documentation

Research

Based on published CRDT research:

• Fugue - Weidner, Gentle & Kleppmann (2023)
• Peritext - Litt, Lim, Kleppmann & van Hardenberg (2021)

License

MIT - see LICENSE