Project Zomboid

Project Zomboid is an open-world isometric survival game developed by The Indie Stone, set during a zombie apocalypse in the fictional Knox County, Kentucky. Players must survive against ever-growing zombie hordes while managing hunger, thirst, exhaustion, illness, and mental health. The game features an exceptionally deep simulation — every item, building, and zombie is individually simulated. In multiplayer, up to 100 players can share a persistent server, cooperating or competing across a massive procedurally detailed map spanning multiple towns.

The game entered Early Access in November 2013 and released Build 41 (the major animation and multiplayer overhaul) in December 2021, causing an all-time Steam concurrent peak of 65,442. Build 42 — adding underground levels, expanded crafting, new animals, and engine improvements — released in unstable single-player form in December 2024, with multiplayer support added in December 2025. The stable branch remains Build 41 as of early 2026.

Project Zomboid's multiplayer uses a dedicated server architecture with UDP as the primary transport protocol. The game does not use Steam Datagram Relay — clients connect directly to server IPs. No official servers exist; the entire multiplayer ecosystem is community-run. Servers are found via the in-game server browser, BattleMetrics, or direct IP. The game has no third-party anti-cheat — it uses its own internal anti-cheat system with 24 configurable protection types. The modding community is large and active, with thousands of Workshop mods, many of which add or alter network-synchronized objects that can affect server performance.