Startup Parameter Builder
Generate optimized startup commands and launch flags for your game server. Supports Minecraft, Rust, CS2, ARK, Valheim, FiveM, and more.
Select Game
Java Edition server with JVM optimization flags
Preset
Memory Settings
Configure RAM allocation for your server
Initial memory allocation
Maximum memory the server can use
JVM Optimization
Advanced Java Virtual Machine settings
Java garbage collection algorithm
Server Options
Basic server configuration
Name of your server JAR file
Port number for the server
Generated Startup Command
java -Xms1024M -Xmx4096M -XX:+UseG1GC -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:+AlwaysPreTouch -XX:G1NewSizePercent=30 -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M -XX:G1ReservePercent=20 -XX:G1HeapWastePercent=5 -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=15 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -XX:MaxTenuringThreshold=1 -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true -jar server.jar --nogui
Tip: Save this as start.bat (Windows) or start.sh (Linux/Mac) in your server directory.
About Startup Parameters
Startup parameters control how your game server launches and operates. For Java-based games like Minecraft, JVM flags can significantly impact performance. Aikar's flags are widely recommended for Minecraft servers and provide excellent garbage collection optimization.
Features
Multi-Game Support
Generate launch commands for Minecraft, Rust, CS2, ARK, Valheim, FiveM, and Palworld
JVM Optimization
Includes Aikar's flags and advanced garbage collection settings for Java-based servers
Download Ready
Copy to clipboard or download as a ready-to-use startup script
How to Use Your Startup Script
🪟 Windows
- 1. Download or copy the generated command
- 2. Create a new text file named
start.bat - 3. Paste the command into the file and save
- 4. Double-click
start.batto launch your server
🐧 Linux / macOS
- 1. Download or copy the generated command
- 2. Create a new file named
start.sh - 3. Paste the command into the file and save
- 4. Make it executable:
chmod +x start.sh - 5. Run with:
./start.sh
Optimization Tips
Match Memory to Your Plan
Set -Xmx (max memory) to 80-90% of your server's available RAM to leave room for the OS and other processes.
Use Aikar's Flags for Minecraft
Aikar's garbage collection flags are battle-tested and recommended for most Minecraft servers. They significantly reduce lag spikes.
Set Min and Max Memory Equal
For dedicated servers, setting -Xms equal to -Xmx prevents heap resizing and improves performance.
Use Correct Java Version
Minecraft 1.17+ requires Java 16+, and 1.18+ requires Java 17+. Using the correct version ensures compatibility and performance.
Consider Your Tick Rate
Higher tick rates (like 128 for CS2) provide smoother gameplay but require more CPU power. Balance based on your hardware.