Mirror Networking vs Netcode for GameObjects

Mirror Networking is a free system for adding multiplayer capabilities to Unity games. It uses a server-authoritative model by default and supports dedicated servers as well as client hosts. Core tools include message handlers, serialization, distributed object management, and state synchronization. Unity components such as NetworkManager, NetworkIdentity, and NetworkBehaviour connect game objects and scripts, with automatic synchronization for transforms and script variables. Built-in transport choices include KCP UDP, Telepathy TCP, WebSockets, a multiplexer, latency simulation, encryption, and Edgegap Relay. Other transport connections include Steam, Epic Online Services, LiteNetLib, and ENet. Mirror is MIT licensed, with no paywalls or CCU costs. The maker says it stores no user data and performs no tracking, analytics, or advertising. Its feature list marks lag compensation and encryption as Beta, unreliable sync mode as in development, and bitpacking and prediction as being researched. The GitHub README recommends Unity 2019, 2020, 2021, 2022 LTS, or 6000.1 to get started.

Netcode for GameObjects is Unity’s high-level networking library for synchronizing GameObjects and world data during multiplayer sessions. Unity describes it as suited to games with smaller player counts and less complex game logic, including adding multiplayer to an existing GameObject-based single-player game. Networking can use client- or server-authoritative models. NetworkBehaviour components use NetworkVariables to synchronize state and RPCs to send messages over the network. Integrated scene management is enabled by default and synchronizes scenes across connected clients. Unity Transport is the default transport, while Unity Relay can provide Relay networking for GameObject and MonoBehaviour workflows. Unity Multiplayer Services sessions are compatible with the package, which handles gameplay state replication after players connect. The package is free, but installation requires an active Unity account with a valid license, a supported Unity version, and an existing project. Supported platforms listed include Windows, macOS, Linux, iOS, Android, XR platforms on those systems, most closed platforms, and WebGL with specified package versions. There is no matchmaking functionality; developers must use third-party services for matchmaking. A full client-side prediction and reconciliation system must also be built by the developer.