Adding mods, plugins and modpacks to a Minecraft server
Adding mods, plugins and modpacks to a Minecraft server
Last updated 2026-08-14
Short answer
A Minecraft server on uniz.host is either running a list of individual mods/plugins or running one whole modpack — never both, because a server stores a single mod source. Individual mods are offered on every Java software except Vanilla; plugins run on the Paper family and the legacy plugin types, mods run on Fabric/Quilt and Forge/NeoForge, and the Mohist/Arclight hybrids take both at once (Modrinth only). A Forge mod cannot load on Paper and a Bukkit plugin cannot load on Forge, so the software you picked at creation decides what you can install. Saving a mod change never interrupts a running server — the new list only takes effect on the next restart, which the pending-restart banner reminds you about.
Steps at a glance
Open the mods tab and choose a setup
Pick a platform, then add each mod
Save while your players keep playing
Restart when the server is empty
Contents
Contents
Two different jobs get filed under the same word. Adding LuckPerms to a Paper server and installing All the Mods on a fresh Forge server both feel like "adding mods", but on uniz.host they are two settings that cannot both be on. This walks through both, which server software accepts which, and the one behaviour that surprises everyone — saving mods does not restart your server.
One server, one mod source
Open a Minecraft server and you get a tab called Mods — or Plugins, if your software runs plugins. Inside, the setup row offers None, an individual list, and on some servers Modpack. They are radio buttons, not checkboxes: your server stores a single mod source, so picking the modpack setup replaces your individual list, and picking the individual list detaches the pack.
The Modpack button is only rendered on servers that were created as a modpack. A Paper or Forge server you built yourself never sees it, because a pack brings its own loader and would fight the software you already chose. Going the other way is possible — a modpack server can be switched to an individual list — but it is a one-way door in practice, for reasons the last section covers.
Bedrock servers get neither. The tab is there, and it contains one line saying mods and modpacks are not available for that edition.
Which software takes mods, which takes plugins
This is the part that costs people an evening. "Mod" and "plugin" are not two words for the same file, and a file built for one loader will not load on the other.
Software you picked
What it runs
Individual list
Vanilla
nothing — no loader at all
not offered
Paper, Purpur, Leaf, Folia
Bukkit-API plugins
plugins
Spigot, Bukkit
Bukkit-API plugins
plugins
Fabric, Quilt
Fabric mods
mods
Forge, NeoForge
Forge mods
mods
Mohist, Arclight
Forge mods and plugins at once
both
In plain words: a Forge mod cannot load on Paper, and a Paper plugin cannot load on Forge. The two hybrids are the exception — they carry a Forge loader and a Bukkit plugin layer in the same server, which is why their card shows a second add button for plugins beside the one for mods.
Vanilla is the only Java software with no loader, so it is the only one where the individual list is switched off entirely, with a line explaining that this server type does not support it. That refusal is enforced on the server side too, not just hidden in the page. Two beta softwares, Pumpkin and Custom, sit outside the picker groups as well and behave the same way.
The software is fixed at creation, but not forever: the version-and-software card can move a server between those thirteen Java softwares. Crossing a family line — say Fabric to Paper — makes every installed file meaningless, so that dialog warns you and makes you tick an acknowledgement that your installed mods will be removed.
CurseForge or Modrinth
Both catalogues are supported, and the choice is per server, not per mod. The platform buttons sit at the top of the card and the browser searches whichever one is selected.
Two things worth knowing before you click. First, switching platform clears your list, on purpose: a pinned version belongs to one catalogue, so carrying entries across would install the wrong file or resolve nothing at boot. The card tells you it cleared the list. Second, CurseForge depends on a platform API key, and the card says plainly that CurseForge may be unavailable if that key is not configured — Modrinth needs no key.
Hybrid servers do not get the choice at all. Mohist and Arclight put mods and plugins into one list, and only Modrinth can express both in a single list, so their card shows a line saying hybrids install via Modrinth only.
Adding individual mods, step by step
Open the mods tab and choose a setup
Go to your server, open the mods (or plugins) tab, and click the individual option in the setup row. You need the Mods permission — server owners have it, team members only if you granted it, and without it every control in the card is greyed out.
Pick a platform, then add each mod
Choose CurseForge or Modrinth, then use the add button to open the catalogue browser. Search, click, done — each pick is added with its newest version that is compatible with this server's software and Minecraft version, so an incompatible pin is not something you can create by accident. If nothing compatible exists, you get told rather than given a broken entry.
Each row afterwards carries the mod's name and the version that got pinned, with Change version to move it and Remove to drop it. A row reading "Version not set" is an old entry from before version pinning; it still works, and re-pinning it is one click. If you already know the project name, the small "add by project name (slug)" toggle opens a plain input.
Save while your players keep playing
Press Save. Nothing on your server moves. The hint under the button says it outright: saving will not interrupt a running server, and changes apply on the next restart. This is deliberate — you can prepare a mod change in the middle of a busy evening and let people play on.
Restart when the server is empty
Because the save only rewrites the template your next pod boots from, your running server is still on the old list. If it was running or starting when you saved, a banner appears saying changes are pending a restart. Hit Restart when your players are offline and the new list is downloaded on the way up.
Installing a modpack instead
On a server created as a modpack, the modpack setup shows the pack currently saved and a picker to choose another. Pick your platform first, then browse — switching platform after a selection clears the pick, for the same reason it clears a mod list.
Two limits are worth planning around. The RAM warning quotes 4GB, and it is a recommendation, not a gate: a smaller plan saves fine and simply risks crashing while the pack loads. And on CurseForge, a pack whose author has disabled third-party downloads is rejected when you save, rather than being accepted and then crash-looping forever with a stuck server.
Expect the first boot to be slow. A big pack downloads everything, builds its loader and generates a world before it can answer a health check, so a booting server is given a 20-minute window before anything treats it as failed — a budget sized after a real pack got killed mid-install on a vanilla-sized one. Watch the console tab while it happens; logs stream while the server is still starting.
Where the files land, and what a pack locks
Everything lives on one volume mounted at /data, which is exactly what the Files tab shows you. Your mods sit in a mods folder (plugins in plugins) next to world at the top level — which is why a world reset can wipe the world and leave your installed files alone, and why uploading a jar by hand into that folder is a real option for anything the catalogues do not carry.
The one thing a modpack takes away is version freedom. A modpack server cannot change its Minecraft version or its software at all — the version card shows a note telling you to detach the pack first, and the API refuses the request. Detaching does not actually buy it back: the server type stays a modpack type, which is outside the switchable set, so the change is refused for a second reason. If you need a different version, build a new server on the pack build you want.
Java runtime — when a pack needs a specific JVM version
Server RAM — how much a modded server actually needs
Dashboard tour — reading the tabs, badges and usage card
Frequently asked questions
Can I add mods to a Vanilla server?
No. Vanilla is the one Java software with no loader at all, so it is the single type excluded from the individual-mods list, and the card says so instead of failing at save time. The API refuses the same request even if it arrives from outside the dashboard. If you want mods on a world you already started on Vanilla, change the software first — the version-and-software card can move a Vanilla server onto Paper, Fabric, Forge and the rest, and your world files carry over.
Can I run a modpack and my own extra mods at the same time?
Not through this card. A server stores exactly one mod source, so choosing the modpack setup replaces the individual list and choosing the individual list detaches the pack. What the files tab does give you is visibility — a modpack server's `mods` folder is a normal folder on your volume, so you can at least see exactly what the pack installed. If you need one extra mod on top, the honest answer is to look for a pack build that already includes it, or run an individual list instead.
Why did my whole mod list disappear when I clicked the other platform?
That is deliberate. A pinned version id belongs to one platform only, and even a bare project name can point at a different project on the other site, so a list carried across would install the wrong files or fail to resolve at boot. The card clears the list and tells you it did. Add your mods again on the new platform before saving, or switch back and leave the list alone.
My plan has less RAM than the modpack warning wants — will it refuse to save?
No. The 4GB figure is a recommendation, not a lock — the card shows an amber warning and saves anyway, and the API deliberately stopped blocking it. What actually happens is decided at boot — a heavy pack on a small plan usually dies while loading and shows up as a crash on the server page. A light pack can be fine. If it does crash on start, more RAM is the fix.
Why can I not change the Minecraft version on my modpack server?
Because the pack owns both the version and the software — the version card shows a note instead of a form, and the API refuses the change outright. Detaching the pack does not unlock it either — a server created as a modpack keeps a modpack server type forever, and that type is outside the switchable set. If you need a different version, create a new server with the pack build you want and move your world across.
The first start after installing a big modpack takes forever. Is it stuck?
Usually not. A large pack has to download every file, build the loader and generate a fresh world before it answers a single health check, so the platform gives a booting server a 20-minute window before anything is allowed to declare it dead. Open the console tab while it boots — logs stream during starting, not just when the server is up. If it exits and restarts in a loop, that is a real failure, and the last error is shown on the server page.