How to make a Vault Hunters server

Vault Hunters is an action RPG grafted onto Minecraft: 5.9 million downloads for the third edition, progression through a talent system, and dungeons generated on demand — the vaults — from which you must bring back 25 artifacts to face the final boss. It's also one of the few packs whose authors state their memory requirement to the megabyte.

The mechanic that changes everything on a server: research

In Vault Hunters, you don't start with the mods. Access to mods is unlocked through research, and that progression belongs to each player individually.

That's the pack's distinctive server characteristic, and it has three immediate consequences:

• everyone advances their own tree. Two players on the same server don't have the same machines available at the same time;
• player data weighs as much as the world. Losing playerdata means losing weeks of research and talents — not just an inventory;
• a player joining late starts their tree from zero, even if the group's world is far along. Decide that up front, as with RLCraft.

Add vault-specific gear, currency and mobs on top: progression is gated end to end, and it isn't something you catch up on.

Vaults are dimensions generated on demand

This is what makes this pack's load different from a conventional exploration pack's.

A vault isn't a room placed in the world: it's a procedural dungeon the server builds the moment someone enters. Every entry is a complete terrain generation — brief and intense.

The concrete consequence: Vault Hunters' load comes in spikes, not continuously. A server humming along quietly can stutter at the precise moment two players each launch a vault. That isn't a misconfiguration — it's the shape of the pack, and it's why you mustn't size it "at rest".

RAM: 8 GB, stated by the authors

The pack's official instructions tell you to set allocated memory to 8192 MB. That's precise, and it's rare.

But that figure refers to the JVM heap (-Xmx), not the machine's memory: the operating system, Docker and Java's off-heap memory live beside the heap. Here, the heap is the smaller of "RAM − 2 GB" and "75% of RAM":

Take the 16 GB tier. The 8 GB tier yields only a 6 GB heap — two gigabytes less than the authors ask for — and on a pack with spiky load, margin isn't a luxury. The creation screen warns you when the tier doesn't cover the pack: it compares heaps, not machine sizes.

Version and Java

Vault Hunters 3rd Edition targets Minecraft 1.18.2 on the Forge loader.

The Java version follows the Minecraft version: the Minecraft Wiki is explicit — "For version 1.18, JRE version 17 is required." That's the kind of detail that fails a manual install without a clear message. Here, the loader and the Java version are derived from the pack: you choose nothing.

And as with any content mod: the client must install exactly the same pack version as the server, or the connection is refused.

The first boot, then the rest

Expect 15 to 25 minutes on first boot: downloading the pack, resolving mods, writing hundreds of configuration files, then generating the world. A vanilla server is ready in two minutes — don't compare the two, and don't kill it thinking it crashed.

Later boots are quick, the world already being there. The vaults, on the other hand, generate on every entry, indefinitely.

Backups: here, this is the critical point

On most packs, backing up protects buildings. On Vault Hunters, it protects each player's research and talents — which is what actually took the time.

The data directory is archived before every shutdown, with a save-all flush immediately before so no minute stays in memory, and restored on the next boot. An automatic backup runs every 30 minutes while you play, of which the last 5 are kept. Storage is free, server off included.

Five rotating backups mean, concretely: if something breaks mid-session, you can go back to a state from two hours ago. On a pack with gated progression, that's the difference between an incident and a lost run.

What not to do

Switch packs, or major versions, on an existing world. The world and player data hold blocks, items and a research state only this pack can read. Loaded elsewhere, they're gone.

Size it from what you see at rest. A Vault Hunters server idling consumes little; at rest is not when to judge it.

Create your Minecraft server and pick Vault Hunters from the modpack list. Your first session is free.