PauseGameFabric

Pause your world automatically as soon as no one is logged onto the server or tabbed out just like singleplayer. You can also install this mod on the client to have a functioning pause menu on multiplayers servers (if all players are paused)

You can also find a version for Spigot here!

Setup

All configuration is optional and is done for you, simply add the the jar to your plugin folder and you're set!

This plugin takes advantage of the tick manager built into Minecraft. It is recommended not to use this plugin if you're already using this system yourself.