derbyjs/racer

Health v2 · maintenance only

Flags: no_license

Adoption not part of the score

1186 stars · 117 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

Racer is a realtime model synchronization engine for Node.js built on ShareDB, providing a unified model and event interface for servers and browsers. It uses Operational Transformation for conflict resolution, supports realtime query subscriptions, offline operation, and persistent storage (e.g., MongoDB).

Use cases

• build collaborative text editors with realtime multi-user editing
• sync application state between browser clients and Node.js servers in realtime
• support offline edits that automatically sync on reconnect
• subscribe clients to specific queries or documents with live updates
• scale realtime apps horizontally across multiple servers with PubSub
• render initial page state on the server and reinitialize the same model in the browser

When to choose

• you need multi-user realtime collaboration with automatic conflict resolution
• your app must keep working offline and sync changes later
• you want one model API shared between server rendering and client interaction
• you're building with Derby or ShareDB and need a higher-level model layer

When to avoid

• you only need simple REST APIs without realtime sync
• you use databases other than MongoDB and don't want to write a ShareDB adapter
• you need built-in, production-ready access control (still under development)
• you prefer a batteries-included framework rather than a model synchronization layer

Facets

library · maturity active

state-management websocket middleware serialization web-development microservices backend browser realtime-sync operational-transformation sharedb offline-first collaborative-apps pubsub real-time nodejs javascript

Member repositories

For agents

markdown · JSON · MCP: product_card(name="derbyjs/racer")