Multiplayer & Netcode

Network transport, replication, lobby/matchmaking, dedicated server hosting. Pairs with Realtime (presence, CRDTs, web-side multiplayer), 3D engines, 2D engines, and distribution / stores (which often bundle networking SDKs). For full landscape see Game Development.

The 2024–26 landscape: Unity's official Netcode for GameObjects is mature; Mirror and FishNet remain the OSS Unity favorites. Photon Fusion is the closed-source-but-free-ish leader. Nakama is the OSS BaaS for multiplayer. Hathora and Edgegap are the indie-friendly hosted server options. Steam Networking is the easy path if you're shipping on Steam.

Unity OSS netcode

• ★ Mirror — free OSS, MIT. The community standard, fork of UNET. Snapshot interpolation, lag compensation, KCP transport. Battle-tested in many shipped games.
• ★ FishNet — free OSS, MIT. More modern than Mirror, prediction + lag compensation built in. Active development.
• Netcode for GameObjects (Unity Multiplayer Center) — free, official Unity. Simpler than Mirror, less plugin ecosystem.
• Netcode for Entities (DOTS) — free, official Unity, ECS-based.

Unity closed-source / hosted

• ★ Photon Fusion 2 — free up to 100 CCU; paid above. Tick-based deterministic netcode with prediction. Replaced PUN/Quantum at the top of Photon's stack.
• Photon Quantum — paid, deterministic ECS netcode for fighting games / RTS.
• Photon PUN 2 — free up to 20 CCU; legacy but still works.
• Mirage — free OSS Mirror fork.

Unreal netcode

• Unreal Replication — built in, the AAA standard.
• Iris Replication System — UE 5.5+, more efficient large-scale replication.
• Steam Sockets / EOS P2P — free transport options for indie shipping.

Cross-engine / web

• ★ Colyseus — free OSS Node.js multiplayer server. Schema replication, rooms, matchmaking. Excellent for Phaser, PixiJS, Unity, Defold. See also Realtime.
• ★ Nakama (Heroic Labs) — free OSS Go server (Apache 2.0). User accounts, matchmaking, leaderboards, in-app purchases verification, social, storage. Self-host or paid Nakama Cloud. The OSS BaaS leader for multiplayer.
• GeckosIO — free, WebRTC + WebSockets fallback for browser games.
• GameNetworkingSockets (Valve) — free OSS, low-level transport from Steam Sockets.
• ENet / enet-csharp — free OSS, classic UDP-with-reliability lib.

Backend-as-a-service for games

• PlayFab (Microsoft) — free tier, paid above. Identity, leaderboards, matchmaking, server hosting.
• ★ Nakama — free OSS or paid cloud.
• GameSparks — sunset.
• Brainwaves — small.
• Pragma, Beamable — paid game-backend platforms.

Dedicated server hosting

• ★ Hathora — paid, indie-friendly orchestrator for game servers. Pay per minute of play.
• Edgegap — paid, edge-deployed dedicated servers.
• Multiplay (Unity Game Services) — paid.
• AccelByte — paid full-stack.
• PlayFab Multiplayer Servers — paid.
• Self-host on Hetzner / OVHcloud / DigitalOcean — cheapest, most work.

Browser / WebRTC

• See Realtime — Liveblocks, PartyKit, Yjs, Centrifugo overlap with browser-game multiplayer.
• GeckosIO — WebRTC for game-shaped use cases.
• Cloudflare Durable Objects — see Realtime.
• PartyKit — Cloudflare Workers + Durable Objects, beloved for tiny multiplayer web games.

Lobby / matchmaking / social

• Steam Lobbies / Steam Networking Sockets — free with Steamworks.
• Epic Online Services (EOS) — free, cross-platform identity, lobbies, P2P. The free Steamworks-shaped option.
• Discord SDK — free, in-Discord lobbies.
• PlayFab Matchmaking, Photon Matchmaker.

Anti-cheat for multiplayer

See anti-cheat.

Pick this if…

• Unity, OSS, default: Mirror or FishNet.
• Unity, generous free + hosted: Photon Fusion.
• Unreal: built-in replication; Iris if scale.
• Web game, Node server: Colyseus.
• OSS BaaS (accounts + matchmaking + storage): Nakama.
• Hosting dedicated servers without DevOps: Hathora or Edgegap.
• Cross-platform indie identity / lobbies: EOS.
• Browser, Cloudflare: PartyKit.