Lag comes from the server running slowly or from the network between you and it. Find out which before changing anything.

Step 1: Check server speed

1. Install Spark if it is not there (Paper includes it). See Spark.
2. Run spark tps.
3. TPS of 20 with short tick times (under 50 ms) means the server is healthy.

Step 2a: Server is slow

1. Run spark profiler start --timeout 300, wait for it to finish, and open the link.
2. Look at which tasks use the most time per tick.
3. Common fixes:
   • Lower simulation-distance in server.properties.
   • Lower mob caps, see Mob Spawn Limits.
   • Remove or replace heavy plugins.
4. For more, see Optimization.

Step 2b: Server is fine but you still lag

This points to the network.

• Run an MTR test, see Diagnosing Ping Issues.
• Restart your router, turn off downloads and try a different connection.

Need help? Share your Spark link in a support ticket.