Why is my Minecraft server lagging?

Paste a spark profiler link. You get what is using the tick time, in plain words, and what to try for each cause.

No link yet? Here is how to get one
  1. Install spark. Paper already includes it.
  2. While the lag is happening, run /spark profiler start.
  3. Wait a few minutes, then run /spark profiler stop.
  4. Paste the link it prints above.

Anyone with a spark link can open it, and spark keeps it for 90 days. A profile can include your plugin list and some config, though spark filters known sensitive settings.

Can't get a link? Use a file, or paste command output

This can show whether the server is struggling. Only a profile can show why.

What it reads

Your browser downloads the profile from spark's own content server and works it out on your device. Nothing from the profile is sent to this site, and there are no accounts, ads or analytics.

Each finding is labelled Measured, Likely or A guess. The rule table lists how every finding is detected and where each piece of advice comes from.