How do I optimise my Minecraft server for better performance?

The single most effective change is switching to Paper if you are not already using it. Paper includes hundreds of performance improvements over vanilla and Spigot. Use the Version Manager to switch, but back up your world first.

For JVM flags, use Aikar's flags. Replace the default startup flags on the Startup page with the following (adjust -Xmx and -Xms to match your plan's RAM, leaving 512 MB free for the OS):

-Xms4G -Xmx4G -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20 -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=15 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PessimisticRefProcMode -XX:+UseFastUnorderedTimeStamps -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true

In server.properties, lower view-distance to 8 or 6. The default of 10 generates significantly more chunk load. Players rarely notice the difference below 10.

In paper.yml (or paper-world-defaults.yml on newer versions), set optimize-explosions: true, mob-spawner-tick-rate: 2, max-auto-save-chunks-per-tick: 8, and use-faster-eigencraft-redstone: true. These reduce tick-heavy operations without changing visible gameplay.

If TPS is low despite the above, check the TPS Monitor page for when drops occur. If they correlate with specific times (e.g., autosave every 5 minutes), adjust the autosave interval in bukkit.yml. If they are constant, identify the plugin or world area causing load by running /tps and /timings report in the console.