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Version: 1.21.x


Communication between servers and clients is the backbone of a successful mod implementation.

There are two primary goals in network communication:

  1. Making sure the client view is "in sync" with the server view
    • The flower at coordinates (X, Y, Z) just grew
  2. Giving the client a way to tell the server that something has changed about the player
    • the player pressed a key

The most common way to accomplish these goals is to pass messages between the client and the server. These messages will usually be structured, containing data in a particular arrangement, for easy sending and receiving.

There is a technique provided by NeoForge to facilitate communication mostly built on top of netty. This technique can be used by listening for the RegisterPayloadHandlersEvent event, and then registering a specific type of payloads, its reader, and its handler function to the registrar.