Minecraft Reference

Minecraft Server Startup Parameters

Configure your Minecraft Java server's startup options: the server JAR, RAM allocation, JVM flags, and console timezone.

Last updated: July 21, 2026

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Server Options in the Game Control Panel sidebar holds the four settings that control how your server launches: which jar file runs, how much RAM it gets, any extra JVM flags, and the timezone stamped on your console logs. You will not need to change these often.

In-game settings like gamemode, difficulty, view-distance, whitelist, and motd are not on this page. See the server.properties guide for those.

Startup Command

The Startup Command field shows the exact command used to launch your server. You do not edit it directly. It is built from the fields below, so change those instead.

The Startup Command modal on the Game Control Panel

PieceWhat it doesWhere to change it
-Xms128MThe initial RAM pool. Aikar’s recommends matching this to Xmx, but on our panel a low starting value that grows on demand works better.Fixed
-XX:MaxRAMPercentage=##The share of your plan’s RAM handed to Minecraft.Max Ram Percentage
server.jarThe jar file that is executed.Server Jar File

Server Jar File

The case sensitive name of the jar file you want to run. Either rename your uploaded jar to server.jar, or set this field to match the file name you uploaded.

The Server Jar File Startup Parameter

Console Timezone

The timezone used for timestamps in your console log. Set it if you want console output to line up with your local clock.

The Console TimeZone Startup Parameter

Max Ram Percentage

How much of your plan’s RAM goes to Minecraft, and how much is left free for the Java Virtual Machine (JVM) to work with. The JVM needs some headroom, and how much varies by Minecraft version and server software.

The Max Ram Percentage server options

Our Aikar’s Flags article explains what that overhead is, why it exists, and why it shifts between versions.

JVM Flags

Extra flags passed to the JVM to fine tune your server’s behavior. They are added after the existing RAM flags and before the timezone flag, but position has no effect on how they run.

  • Aikar’s flags are the most common set. They are configured by default on all of our 8GB and larger packages, and you can add them manually on smaller plans. Our Aikar’s Flags article covers what they do and what WinterNode’s policy on them is.
  • -Dpaper.useLegacyPluginLoading=true enables the legacy plugin loader on Paper servers.

server.properties file

Looking for in-game settings like gamemode, difficulty, view-distance, whitelist, or motd? Those live in the server.properties file, not the startup parameters. See the dedicated server.properties guide for every option with current defaults and recommended values.

Frequently Asked Questions

No. The Startup Command field is built from the other fields on the Server Options page. Change the Server Jar File, Max Ram Percentage, or JVM Flags field and the command updates with it.

No. Your flags are inserted after the RAM flags and before the timezone flag, and that position has no effect on how they run.

Those are in-game settings, not startup settings. They live in the server.properties file, which has its own guide.