Engine-Level Multiplayer Netcode

Building netcode that is fast, fair, and stable requires decisions at the transport, protocol, simulation, and presentation layers. This skill gives the full architecture used by modern FPS/MOBA engines, independent of any specific engine — then shows how each engine (Unity/Unreal/Godot) maps onto it.

1. Core Architecture

Client                                Server
  Input sampler (fixed rate)      ->  Input validator
      |  (unreliable channel)         Simulation (authoritative, fixed tick)
  Local Prediction (client sim)       Snapshot builder (delta vs ack)
  Interpolation buffer               Priority queue (interest management)
  Reconciliation (rebase on snap) <-  Unreliable snapshots (30-60Hz)

The Rule of Three