Accepts messages from external sources. Associated with a core. Sends incoming events to the core’s streams, queries the core’s index for states.


(gen-udp-handler core stats channel-group handler)


(udp-handler core stats ctx message)

Given a core, a channel, and a message, applies the message to core.


(udp-server)(udp-server opts)

Starts a new UDP server. Doesn’t start until (service/start!).

IMPORTANT: The UDP server has a maximum datagram size–by default, 16384 bytes. If your client does not agree on the maximum datagram size (and send big messages over TCP instead), it can send large messages which will be dropped with protobuf parse errors in the log.


  • :host The address to listen on (default
  • :port The port to listen on (default 5555).
  • :max-size The maximum datagram size (default 16384 bytes).
  • :so-rcvbuf The socket option for receive buffer in bytes (SO_RCVBUF)
  • :channel-group A ChannelGroup used to track all connections
  • :initializer A ChannelInitializer