Server software
new downloads or builds the server you name, and Add a server in the panel offers the same list. Every option runs with a plain -jar, so the supervisor is indifferent to which; the differences are where the software comes from, how it is verified, and what it loads.
| Flag | Software | Loads | Source and verification |
|---|---|---|---|
--paper <v> | Paper, newest stable build | Plugins | PaperMC, sha256 |
--purpur <v> | Purpur, a Paper fork with more configuration | Plugins | purpurmc.org, md5 |
--folia <v> | Folia, Paper with regionised multithreading | Folia-built plugins only | PaperMC |
--asp <v> | Advanced Slime Paper, Paper with Slime World Manager built in | Plugins | InfernalSuite, sha256 |
--spigot <v> | Spigot | Plugins | Compiled on your machine by BuildTools |
--craftbukkit <v> | CraftBukkit | Plugins | Compiled on your machine by BuildTools |
--vanilla <v> | Mojang's own server | Nothing | Mojang, sha1 |
--fabric <v> | Fabric launcher | Mods | FabricMC |
--neoforge <v> | NeoForge, through its installer | Mods | NeoForged maven, sha256 |
--modpack <slug> | A whole Modrinth modpack | Its mods | Modrinth |
--jar <file> | A jar from the jar store | Depends on the jar | Local |
--template <name> | A saved plugin and config set | Depends on the template | Local |
--build <n> selects a specific build where the source numbers builds (Paper, Folia, Purpur).
Spigot and CraftBukkit
SpigotMC publishes no jars, so BuildTools compiles them on your machine.
| Requirement | Detail |
|---|---|
| Java | A JDK (javac, not only a runtime) |
| git | Fetched as a portable copy; nothing to install |
| First build of a version | Five to ten minutes |
| Disk | About 1 GB of clones under jars/buildtools/, reused so later builds are faster |
| Progress | The panel narrates the build line by line |
Plugins follow the software
The Plugins tool searches for what the server can load. Fabric and NeoForge servers get a Mods tool instead.
| Software | Plugin search |
|---|---|
| Paper | Modrinth and Hangar |
| Purpur | Modrinth, for Purpur, Paper, Spigot and Bukkit builds |
| Folia | Folia-built plugins only |
| Spigot, CraftBukkit | Spigot and Bukkit builds |
| Vanilla | Nothing to manage; the tool says so |
| Fabric, NeoForge | Modrinth mods for the loader |
Updating server software
| Software | upgrade support |
|---|---|
| Paper, Purpur, Folia | Newest build for the current Minecraft version, or a newer Minecraft version |
| Advanced Slime Paper | Same. Builds have no number, so they are compared by date. |
| Spigot, CraftBukkit, vanilla, Fabric, NeoForge | Create a new server, or import a newer jar |
The routine path installs the newest build of the same Minecraft version and keeps the old jar as the way back. Crossing Minecraft versions is a separate, confirmed path that takes a snapshot first, because worlds migrate one way. Settings → Server software shows the running build and offers either move.
Java per server
Each server picks its own Java, so a 1.20.4 server on Java 17 can run beside a 26.x server on Java 25.
| Minecraft version | Java |
|---|---|
| 1.18 to 1.20.4 | 17 |
| 1.20.5 to 1.21.x | 21 |
| 26.x | 25 |
SpawnLoft finds what is installed, picks the newest Java that fits when a server is created, and refuses a version nothing installed can run before the download starts, with a link to the Java it needs. --force on new and start proceeds anyway. Point a server at a specific Java with spawnloft set <name> java=<path>.