Slumber

What Slumber doesSlumber is a server-side mod that freezes the game loop when zero players are connected. The server stops ticking entirely, or runs at a reduced tick rate you define, until someone joins again. This cuts CPU and memory use on idle servers without shutting the process down.## Who it's forServer operators who run communities with off-peak hours, test instances that sit idle between sessions, or anyone paying for host resources they don't need 24/7. It works on Fabric, Quilt, Forge, NeoForge, Paper, Spigot, Folia, Purpur, and Sponge.## Main capabilitiesFreeze on empty - after the last player leaves, a configurable delay (default 20 seconds) passes before the server enters slumber. You can disable the feature entirely with /slumber false or re-enable it with /slumber true.Adjustable tick rate - the sleep_tick_speed setting lets you pick a reduced TPS instead of a full freeze. A value of 0.0 means complete stop; any positive number runs the loop that slowly.Optional autosave - when sleep_autosaving is true, the server still writes world data while frozen.Safe startup - with safe-starting enabled (default), the server stays frozen during initial terrain generation so redstone contraptions don't fire before chunks are ready.Status command - /slumber reports whether the mod is enabled, whether the server is currently frozen, and whether deep chunk unloading is active.## Compatibility notesMinecraft versions before 1.20.3 require the fabric-carpet mod on Fabric/Quilt. For Paper, Spigot, and Folia you must install the Ignite Mixin loader and run its jar alongside the server jar; Folia also needs the jar renamed to paper.jar or launched with specific JVM arguments. Sponge users drop the plugin in the plugins folder. The mod declares support for a long list of discrete versions from 1.20.3 through 1.21.11 plus several 26.x snapshots; it doesn't claim support for versions outside that list.## ConfigurationAll settings live in <SERVER_DIR>/config/slumber.properties using a simple key=value format. The file includes the delay, debug logging toggle, safe-starting flag, complete-freeze option, and the default enabled state.