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spark is a free profiler that shows which plugin, mod, entity or task is making your Minecraft server lag. Paper bundles it from 1.21, so run spark profiler start --timeout 600 in the console while the lag happens. After 10 minutes you get a link to a report showing where the server spends its time. On Fabric, Forge or NeoForge, install spark from Mods first.

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Before you start

  • Paper 1.21 or newer: spark is already there. Don’t install it again.
  • Other server types: install spark from Plugins or Mods and restart. See install mods.
  • Profile while the lag happens, ideally with players online.

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spark commands

Type these in the Console without / (in game, add / and you need permission).

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How to profile lag with spark

1

Check TPS

Run spark tps. If TPS is 20 and tick times are low, the server isn’t lagging: the problem is the player’s connection or PC.
2

Start the profiler

Leave it running for 10–15 minutes while players play normally.
3

Open the report

When it stops, the console shows a link. Open it in your browser.
4

Find the slow part

Expand the tree from the top. Follow the branches with the highest percentage. Plugin and mod names show where their code runs, for example a plugin’s name next to a task, or entityTick for entities.
5

Act on it

Update, configure or remove the plugin or mod that uses the most time. For entities, cut down farms and mob counts. See the lag checklist.
Want help reading the report? Paste the spark link into a ticket.

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How to check memory with spark

If memory sits at your plan’s limit, run:
Open the link. The top entries show which objects use the most memory. Many entities or chunks point at farms or view distance; a plugin’s or mod’s name points at that plugin or mod. See server crashing or out of memory.

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What do common spark results mean?

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What do TPS and MSPT mean?

Minecraft runs 20 ticks per second, so each tick has 50 ms. When ticks take longer than 50 ms on average, TPS drops below 20 and players notice lag. spark tps shows both values. MSPT tells you how close you are to the limit even while TPS is still 20.

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Frequently asked questions

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Is spark built into Paper?

Yes. PaperMC bundles spark from Minecraft 1.21, and it is their preferred way to profile. You don’t need to install it on Paper.

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How long should I run the profiler?

10–15 minutes during normal play gives a clear picture. Short profiles can miss lag that comes and goes.

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Does spark cause lag itself?

spark is made to run on a live server, so you can profile while players are online. Stop it when you’re done.

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What TPS is good?

20 TPS is perfect. Players start to notice below about 18.

Minecraft server guide

Every Minecraft guide in one place.

Fix server lag

The full lag checklist.

Pre-generate with Chunky

Stop exploration lag.

Server console

Run commands from the panel.
Checked against the official spark documentation and PaperMC documentation on 29 October 2026, and tested on our Game Panel (Minecraft 26.1, Paper and Fabric). Steps may differ slightly if spark changes.

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Need Extra Help?

If you encounter any issues, our support team is ready to assist:

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Last Updated: October 2026