Colyseus vs netcode.io

Colyseus is an open-source Node.js framework for building real-time multiplayer games, with built-in matchmaking and state synchronization. Its authoritative server design has clients send inputs while the server decides game outcomes. Developers define game state on the server, and Colyseus synchronizes it to clients without manual serialization. The framework creates rooms and matches players automatically; rooms can be distributed across processes or machines. The site says this can scale from 10 to 10,000+ concurrent users. SDKs or integrations are listed for JavaScript, Unity, Godot, GameMaker, Defold, Haxe, C, and Construct 3. The MIT-licensed framework is free for commercial games and can be self-hosted as a standard Node.js application on cloud services or bare metal. Colyseus Cloud provides deployment, scaling, and monitoring across 32 global locations. Its Cloud plan starts at $15/mo and includes email support, while the free Open Source plan includes community support. Cloud has no free tier or automatic scaling; heavier workloads require upgrading deployment resources through the dashboard.

netcode.io is a free, open-source client/server protocol for real-time multiplayer games. It uses UDP to exchange unreliable, unordered packets without TCP head-of-line blocking. Game backends can issue connect tokens that authorize clients, while servers assign connecting clients to configured slots and reject connections when slots are full. The protocol supports clean disconnects and timeouts for hard disconnects. Packets are encrypted and signed with libsodium, with protections described against crafted packets, replay attacks, and amplification attacks. IPv4 and IPv6 are supported, along with packet tagging intended to reduce Wi-Fi jitter. Implementations are listed for C, C#, Go, Rust, Unity, Unreal Engine 4, and TypeScript. Builds use CMake on Windows, macOS, and Linux, with CMake 3.16 or later and a vendored libsodium subset by default. The BSD 3-Clause project documents REST-based token requests and reports a nonce-reuse issue affecting versions 1.3.5 and earlier, fixed in 1.4.0.