Nchan

Nchan is a scalable, flexible pub/sub server for the modern web, built as a module for the Nginx web server. It can be configured as a standalone server, or as a shim between your application and tens, thousands, or millions of live subscribers. It can buffer messages in memory, on-disk, or via Redis.

Some features:

• RESTful, HTTP-native API.
• Supports Websocket, EventSource (Server-Sent Events), Long-Polling and other HTTP-based subscribers.
• No-repeat, no-loss message delivery guarantees with per-channel configurable message buffers.
• Subscribe to hundreds of channels over a single subscriber connection.
• HTTP request callbacks and hooks for easy integration.
• Introspection with channel events and url for monitoring performance statistics.
• Channel group usage accounting and limits.
• Fast ephemeral local message storage and optional, slower, persistent storage with Redis.
• Horizontally scalable (using Redis).
• Highly Available with no single point of failure (using Redis Cluster).