alpaca-netcode: Rollback/replay NetCode for realtime, deterministic, multiplayer games.

[ apache, game-engine, library, network ] [ Propose Tags ]

A rollback/replay client-server system for realtime multiplayer games. The API only requires you to express your game as a pure, deterministic function.

See Alpaca.NetCode to get started.


  • Simple code. Your game logic contains no NetCode.

  • Low bandwidth. Only inputs are shared.

  • Zero latency. Player's own inputs affect their game immediatly.

  • UDP based. Unordered and using redundancy to mitigate packet loss.

  • Lightweight server. The server does not run the game logic, it only relays and tracks user inputs.

  • Cheating. Only inputs are shared which eliminates a whole class state manipulation cheats.


  • Increased CPU usage. Rollback/replay means that clients must run the game step function multiple times per frame.

  • Not suitable for large numbers of players. Tens of players is likey reasonable.


This is an initial release with minimal functionality and still very experimental. Use at your own risk.


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Dependencies base (>=4.9 && <4.16), bytestring, containers, flat, hashable, network (>=3.1 && <3.2), network-run, random, stm, time [details]
License Apache-2.0
Copyright 2021 David Eichmann
Author David Eichmann
Category Network, Game Engine
Source repo head: git clone
Uploaded by DavidEichmann at 2021-04-02T22:23:32Z
Downloads 275 total (7 in the last 30 days)
Rating 2.0 (votes: 1) [estimated by Bayesian average]
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