Deterministic Multiplayer Framework

The hard half of multiplayer, already built.

Most multiplayer starter kits hand you a networking library and leave the hard

parts to you: keeping every player in sync, deciding who is authoritative about

a hit, and stopping cheaters. This framework gives you that foundation already

built, networked, and cheat-resistant, so your time goes into your game instead

of netcode plumbing.

SET UP IN A FEW CLICKS — NO CODING

Import the package and open the Framework Manager. The Build My Game wizard

walks you through a short checklist, builds the scene, and wires everything up.

A few clicks later you press Play, click Host, and you have a running

server-authoritative multiplayer game with a join code your friends can use.

No coding at any point. No third-party networking package to buy or install —

a UDP transport is bundled and is the default online path, with UPnP and STUN

so join codes work across the internet without relay fees.

READ THIS BEFORE YOU BUY

This is a multiplayer foundation, not a finished or polished game.

Characters are capsule primitives with simple materials. The package ships no

character models, no animations, no audio, and no level art — the only included

art is a health-bar UI. What you get is the simulation, the netcode, and the

architecture underneath a game, all working and all covered by an automated

test suite. The look of your game is yours to build on top.

If you want a playable game you can reskin, this is not that. If you want the

multiplayer engineering solved so you can focus on your actual game, this is

exactly that.

HOW IT WORKS

A deterministic, fixed-step simulation runs on a tick loop with a

server-authoritative model. Clients send input. The server runs the simulation

and decides outcomes. Results replicate back to everyone.

It is the same architecture competitive shooters and MMOs use to stay fair and

consistent under latency — here it is already wired up and running.

TWO PLAYABLE TEMPLATES

Arena Shooter — a live server-authoritative multiplayer game. Host or join with

a code, move, shoot, and fight networked NPCs. Runs on the bundled transport

with no extra install.

Offline Prototype — the same systems running single-player with no networking

at all. The place to learn how everything fits together before you go online.

WHAT'S INCLUDED

Deterministic tick loop — a fixed-step simulation heartbeat at a tick rate you

choose (30 Hz default, fully configurable for anything from a 10 Hz persistent

world to a 60 Hz shooter). The same inputs always produce the same result.

Server-authoritative movement — responsive under latency through client

prediction and server reconciliation, without ever trusting the client.

Reconciliation thresholds scale automatically with velocity, so a 100 m/s

vehicle predicts as smoothly as a walking character. No teleport or speed

cheats.

Lag compensation — when a client fires, the server rewinds every other entity

to where that client saw them at their fire tick and resolves the hit against

those positions. Players do not have to lead their targets by their own ping.

The compensation window is bounded and configurable per genre.

Smooth remote players — incoming snapshots are buffered and interpolated

between two known states rather than extrapolated, so remote players do not

overshoot and snap back when they change direction. Bounded extrapolation

covers packet loss.

Server-validated combat — hitscan and projectile weapons, plus melee, all

resolved on the server against authoritative positions. Clients cannot fake a

hit. All client input is range-clamped and sanitised server-side.

Networked NPC AI — a ready-made enemy with chase, melee, and wall-climb

behaviour, simulated on the server and replicated to every client.

Factions — assign players and NPCs to teams with friendly, hostile, and neutral

stances.

Death and respawn — full death detection and respawn scheduling, built in.

Pluggable gravity — swap uniform gravity for custom sources without touching

movement code.

Session handling — clients detect when the host leaves, stop cleanly, and

report why instead of continuing in a dead session.

Test under real conditions — inject latency, jitter, and packet loss from the

Inspector and test your game at 200 ms and 5% loss without leaving the Editor.

Stability systems — area-of-interest filtering and time-dilation safety keep

the simulation stable under load instead of breaking.

DATA-DRIVEN — NO CODE REQUIRED

Weapons, factions, NPC behaviour, and movement are authored as

ScriptableObjects. Duplicate an asset, change the numbers in the Inspector,

press Play. You can build and balance an entire game without writing a line of

code.

CLEAN, EXTENSIBLE ARCHITECTURE

Systems talk through well-defined interfaces rather than tangled direct

references. Add your own simulation phases, swap implementations, or build on

top.

The netcode layer is a swappable adapter. The bundled UDP transport is the

default, and a FishNet adapter is included for developers who already use

FishNet or want its feature set — install FishNet and the framework detects it

automatically. You are not locked to one networking library.

Full C# source included.

DOCUMENTATION

A beginner-friendly guide covers the core concepts, both templates, scene

setup, customisation, and troubleshooting. Written for developers who have

never built a networked or deterministic game before.

REQUIREMENTS

Unity 6 or newer, Universal Render Pipeline (URP).

Requires the Unity Input System package. This framework does not support the

legacy Input Manager. Active Input Handling must be set to "Input System

Package (New)" or "Both".

Required Unity packages, installed automatically via Package Manager and not

redistributed by this asset: Input System, Newtonsoft Json, Mathematics, Burst,

Collections, and uGUI. Installing the Input System may prompt Unity to restart

the Editor.

WebGL is not supported for online play on the bundled transport.

NOT INCLUDED

Character models, animations, audio, level art, matchmaking, dedicated server

hosting, or account services.

THIRD-PARTY SOFTWARE

This asset uses LiteNetLib under the MIT License, NATS.NET under the Apache

License 2.0, Npgsql under the PostgreSQL License, and StackExchange.Redis,

Pipelines.Sockets.Unofficial and .NET runtime libraries under the MIT License.

See Third-Party Notices.txt in the package for details.