Server Setup
How to Install a Fabric Server
Fabric is the fast, light way to run a modded Minecraft server. Download the launcher, drop in Fabric API plus a couple of performance mods, and you get a snappy server that boots in seconds with Loading N mods ... done in the console.
Why mods go in mods/
Fabric Loader scans the mods/ folder at boot and resolves dependencies in order, which is why fabric-api must be present before anything that needs it. Keep server-side-only mods (Lithium, FerriteCore, spark) here so vanilla clients can still connect, and put any content mods on both the server and every player.
Quick answers
+What is the difference between Fabric and Forge?
Fabric is a lightweight modloader that updates fast and runs lean; Forge is heavier with deeper API hooks. Mods are not cross-compatible, so pick the one your mods target.
+Do I always need Fabric API?
Almost. Most Fabric mods depend on fabric-api for shared hooks. Install it first or those mods fail to load with a "missing dependency" error in console.
+Why won't my server start?
Common causes: eula not set to true, a Java version mismatch (1.21 needs Java 21), or a mod built for a different Minecraft version. Read the first red line in the log.
+How much RAM should I give it?
2-4GB is fine for a small vanilla-plus Fabric server. Set it with -Xmx4G -Xms4G in your start command. Add more only as players and mods grow.
+Can players use a vanilla client?
Only if every installed mod is server-side (Lithium, FerriteCore, spark). Any mod that adds blocks or items means players must run Fabric with the same mods.
+Where do I set the world and player limit?
In server.properties, generated on first run. Edit level-name, max-players, gamemode and difficulty, then restart for the changes to apply.