Zombie apocalypse servers are survival-focused worlds where zombies are the main threat, usually with higher spawn rates, tougher or custom zombie variants, and limited safe zones. Players scavenge for food and gear, build or fortify bases, and often team up in small groups to survive raids and night cycles. Many run plugins or mods for guns, melee weapons, infection systems, loot crates, and wave events to make it feel more like an outbreak than vanilla survival.