A performance profiler for Minecraft
clients, servers, and proxies.


spark is a performance profiler, made up of three main components.


spark can help to diagnose performance problems and bottlenecks with its built-in profiler.

Memory Inspection

spark can produce full heap dumps, present a summary of what’s using the most memory, and monitor GC activity.

Health Reporting

spark monitors and reports a number of key metrics which are useful for tracking performance over time.

More information about spark can be found on GitHub, or you can come chat with us on Discord.


This website is also an online viewer for spark data.

In order to use it:

  1. Generate a profile or heap summary using the appropriate spark commands.
  2. After the data has been uploaded, click the link to open the viewer.

You can also generate or export a .sparkprofile or .sparkheap file and open it by dragging it into the box below.

The website/viewer is written in JavaScript using the React framework, and open-source'd on GitHub. Pull requests are much appreciated!