SkyFactory at a glance
| Current edition | SkyFactory 5 - Minecraft 1.19.2 with Forge, Java 17 |
|---|---|
| Predecessor | SkyFactory 4 - Minecraft 1.12.2 with Forge, Java 8; still widely played |
| Concept | skyblock: start on an island in the void, progress via sieves and automation |
| World generator | via the mod Topography and the generator-settings entry - not via level-type |
| World types | SkyFactory 4 brings over 30 presets (Classic, Skygrid, Compactsky, Sea World and more) |
| Source | CurseForge - installable with a click in the panel |
| World size | very small - hardly any terrain is generated |
| Bottleneck | item entities and tick time, not storage |
| Recommended plan | plan L - the pack states 6 GB as the minimum allocation |
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SkyFactory server hosting
Prepaid from €2.99 / month, unlimited slots, no minimum term. The right plan is listed in the RAM table below.
Plans & pricesThe world generator - this is where everything is decided
With no other pack is the first server start as consequential as with SkyFactory. A skyblock pack needs a void world: no ground, no biomes, just a starting island. If the server is started with the default values, a perfectly normal Minecraft world is created instead - and the entire concept is gone, because every resource can simply be mined.
This is where the most common misconception lies: this is not controlled via level-type, but via the mod Topography, which SkyFactory brings along. It reads its preset from the generator-settings entry in server.properties. For the classic island worlds, level-type stays at DEFAULT:
level-type=DEFAULT
generator-settings={"Topography-Preset":"Sky Factory 4"}The preset name in quotation marks decides the starting world. SkyFactory 4 brings over 30 of them - from the classic island to Sea World, Stone Factory and Lava Factory. Individual special types differ and additionally set their own level-type, such as skygrid or compactsky; the latter also takes a size in the preset. The valid names for your edition are in the pack description on CurseForge - copy them from there, as they differ between SkyFactory 4 and 5.
The order is decisive: the entry must be in place before the world is generated for the first time. If a normal world has already been created, no later change helps - chunks that have already been generated stay as they are. Then the only option is to delete the world folder and start again. As long as nobody has built anything yet, that is done in two minutes; after two weeks of play, it is annoying. What each line of the file does is explained in server.properties.
Why a tiny world still puts load on the server
SkyFactory worlds take up hardly any storage - almost no terrain is generated. Yet this pack of all packs regularly makes servers stumble, and via a route you would not expect from an empty world: item entities.
The concept consists of multiplying material. Cobblestone generators produce non-stop, sieves break gravel down into ores, trees are felled and processed automatically. If a chain somewhere fills up or a consumer is missing, the items fall to the ground - and every single one of them is an entity that the server computes in every tick. A few thousand leftover items are enough to push TPS down noticeably.
The effect typically occurs when nobody is watching: overnight, while the chunks stay loaded. The countermeasures are simple, though - consistently route overflows into lava or a void disposal, only let automation run as fast as its consumers, and check the entity count in the console if in doubt. How to do that is described in Lag and TPS.
SkyFactory 4 or 5?
SkyFactory 5 is the current edition, built on Minecraft 1.19.2 with Forge and Java 17. It is the obvious choice for a new run.
SkyFactory 4 still runs on many servers, and for an understandable reason: it is built on Minecraft 1.12.2, has settled over years and is considered by many to be the more rounded experience. The price is the same as with RLCraft - you have to set the Java version to Java 8, because Forge for 1.12.2 does not start with Java 17 or 21. In the web interface, this is done under Startup in the Docker Image field.
Otherwise, the two hardly differ for the server: small world, moderate memory requirements, tick time as the bottleneck. The decision is a matter of taste, not technology.
Which plan for SkyFactory?
The thresholds below apply to this pack - a light Vanilla+ pack and a kitchen-sink pack with a hundred running machines behave completely differently. You can upgrade at any time without losing data and only pay the difference.
| Group | Plan | RAM | Price | Why | Order |
|---|---|---|---|---|---|
| Solo or two players | Plan M | 4 GB | €5.99 / month | Runs, but with 4 GB is below the 6 GB stated as the minimum allocation. | Order M |
| 3-8 players | Plan L | 8 GB | €11.99 / month | The normal case - several islands with permanently running generators, clearly above the minimum recommendation. | Order L |
| From 10 players | Plan XL | 16 GB | €21.99 / month | Many parallel islands, all producing at the same time. | Order XL |
| Storage | Plan M | 4 GB | €5.99 / month | Even the smallest sensible plan has plenty of headroom - the world stays tiny. | Order M |
The memory is taken proportionally from the plan via -XX:MaxRAMPercentage - you don't need to maintain a fixed -Xmx. The basics are covered in the RAM guide.
Setting up SkyFactory on the server
- Decide which edition will be played - SkyFactory 5 on 1.19.2 or SkyFactory 4 on 1.12.2.
- Stop the server in the web interface.
- In the guided setup, choose Forge and search for the edition via the CurseForge installer.
- Under Startup, set the Java version: Java 17 for SkyFactory 5, Java 8 for SkyFactory 4.
- Before the first start, set the Topography preset in
server.properties:generator-settings={"Topography-Preset":"..."}with your edition's preset name;level-typeusually stays atDEFAULT. - Start the server, wait in the console for
Doneand check that the starting island sits in the void - not on a normal landscape.
Common pitfalls with SkyFactory
A normal world instead of a skyblock island
Cause: The Topography preset under generator-settings was missing from server.properties on the first start. Without the entry, the server creates an ordinary world - even if level-type is correctly set to DEFAULT.
Fix: Set the value according to the pack description, delete the world folder and let it regenerate. A later change does not repair existing chunks.
TPS collapse overnight
Cause: Automation keeps producing without consumers; the surplus items lie as entities in loaded chunks.
Fix: Consistently dispose of overflows, adjust production rates to the consumers and check the entity count in the console.
SkyFactory 4 does not start
Cause: The server runs on Java 17 or 21. Forge for Minecraft 1.12.2 cannot cope with that.
Fix: Under Startup, switch to Java 8 and restart - see Change the Java version.
Players fall into the void when joining
Cause: The spawn point is next to the starting island because the world was generated without a matching spawn island.
Fix: Set the spawn point on the island or let the world regenerate. For fresh runs, regenerating is the quicker route.