Lifecycle Events

dev.architectury.event.events.common.LifecycleEvent

Fires as the server starts up, shuts down, loads or saves levels, and syncs its data to players. Use these to set up and tear down server-side state at the right moment. All of these are notifications (you can't cancel them).

Events

Event	Listener receives	When
SERVER_BEFORE_START	MinecraftServer	The earliest point the server is available.
SERVER_STARTING	MinecraftServer	During server startup.
SERVER_STARTED	MinecraftServer	Server is ready to accept players.
SERVER_STOPPING	MinecraftServer	Server has begun shutting down.
SERVER_STOPPED	MinecraftServer	Server has fully stopped.
SERVER_LEVEL_LOAD	ServerLevel	A level was loaded on the server.
SERVER_LEVEL_UNLOAD	ServerLevel	A level was unloaded on the server.
SERVER_LEVEL_SAVE	ServerLevel	A level is being saved.
SETUP	- (Runnable)	Common setup has begun. Registries should be populated by now.
TAGS_UPDATED	tagsUpdated(RegistryAccess registries, boolean client)	Tags have finished loading and are ready to use.
DATAPACK_SYNC	sync(ServerPlayer, boolean joined)	Data pack contents are about to be sent to a player.

The server-state events use the ServerState listener (stateChanged(MinecraftServer)); the level events use ServerLevelState (act(ServerLevel)).

Added in 21.1

TAGS_UPDATED and DATAPACK_SYNC were added in Architectury API 21.1.

Example

LifecycleEvent.SERVER_STARTED.register(server -> {
    System.out.println("Server is up with " + server.getPlayerCount() + " players");
});

LifecycleEvent.SERVER_LEVEL_LOAD.register(level -> {
    // initialize per-level data
});

Tags and data pack syncing

TAGS_UPDATED fires once tags are bound and safe to query. The client flag is true when this happened on the client as a result of receiving tags from a server, and false on the server. It mirrors NeoForge's TagsUpdatedEvent and Fabric's CommonLifecycleEvents.TAGS_LOADED.

DATAPACK_SYNC fires once per player that data pack contents are about to be sent to, either because the player joined or because the server reloaded its resources. The joined flag tells the two cases apart: true for a fresh join, false for a reload. It mirrors NeoForge's OnDatapackSyncEvent and Fabric's ServerLifecycleEvents.SYNC_DATA_PACK_CONTENTS, and is the right place to send your own data-driven content to the player.

LifecycleEvent.TAGS_UPDATED.register((registries, client) -> {
    // rebuild any caches you keep that are keyed on tags
});

LifecycleEvent.DATAPACK_SYNC.register((player, joined) -> {
    // send your mod's data-driven content to `player`
});

note

For the client equivalents (CLIENT_STARTED, CLIENT_STOPPING, CLIENT_LEVEL_LOAD, CLIENT_SETUP), see Client Lifecycle Events.