- A
.mrpackis a zip with a list of mods to download (modrinth.index.json) and a folder of configs (overrides). - To run it as a server you need the right loader and Minecraft version, every mod marked as server-compatible, and the overrides.
- Some packs publish a ready-made server pack. Use it if there is one.
- On NS5, paste the modpack's Modrinth link into the Plugins tab and it's done for you.
What's inside a .mrpack
Rename a .mrpack to .zip and open it. You'll find:
modrinth.index.json: the Minecraft version, the loader and its version (Fabric, Forge, NeoForge or Quilt), and a list of files with download links and checksums. Each file can be marked as required, optional or unsupported on the client and on the server.overrides/: configs, default options, KubeJS scripts and anything else the pack author ships. Copied into the instance as-is.- Sometimes
server-overrides/andclient-overrides/for files that only belong on one side.
The mods themselves aren't in the file, which is why you can't just unzip it into a server folder.
Option 1: use the pack's server files
On the modpack's Modrinth page, check the Versions tab and the description for a "server pack" or "server files" download. If the author provides one, it's the most reliable route: upload it, start it with the included script and accept the EULA.
Option 2: build the server yourself
- Read the index. Open
modrinth.index.jsonand note the Minecraft version and the loader version underdependencies. - Install that loader on your server at exactly that version. See making a modded server for Fabric and Forge.
- Download the server-side mods. For each entry in
files, skip it ifenv.serverisunsupported; otherwise download it to thepathgiven (usuallymods/…). Tools such as mrpack-install automate this from the command line. - Copy the overrides. Copy the contents of
overrides/(andserver-overrides/if present) into the server's root folder. - Set memory and start. Give it enough RAM (see below), accept the EULA and start. The first boot of a big pack can take several minutes.
Option 3: one-click install on NS5
- Copy the modpack's link from modrinth.com, for example
https://modrinth.com/modpack/fabulously-optimized. You can also link a specific version. - On your NS5 Minecraft server, open the Plugins tab and paste the link into the modpack box.
- NS5 reads the pack, switches your server to the right Fabric or Forge version, downloads every server-side mod from Modrinth's CDN with checksum checks, skips client-only files and copies in the configs.
- Start the server.
Packs built on NeoForge or Quilt need a loader we don't offer yet; the installer tells you if that's the case.
How much RAM a modpack needs
| Pack | Typical RAM |
|---|---|
| Optimisation or "vanilla+" packs (under ~100 mods) | 3–5 GB |
| Medium content packs (100–200 mods) | 6–8 GB |
| Large kitchen-sink or tech packs (200+ mods) | 8–12 GB |
Many pack pages list a recommended amount; follow it and add 1–2 GB per handful of extra players. The RAM calculator can estimate it from the mod count.
Getting players on the same pack
Players install the same pack and version in the Modrinth App, Prism Launcher or another launcher that supports .mrpack. When you update the server to a new pack version, everyone updates their client to match.
Updating a modpack
- Take a full backup.
- Read the pack's changelog. Removed mods can delete their blocks from your world.
- Install the new version the same way you installed the old one. Keep your
worldfolder and any configs you changed on purpose. - Start the server and check the console before letting players in.
Common questions
Can I put a CurseForge modpack on a server the same way?
CurseForge packs use a different format. Most CurseForge packs offer a separate server pack download on their Files page, which is the easiest way to set one up.
Why does my modpack server crash on startup?
The usual causes are a client-only mod left in the mods folder, a loader version that doesn't match the pack, or not enough RAM. The crash report in crash-reports/ names the mod involved.
Do I need the same pack version as the server?
Yes. Players should run exactly the same pack version as the server, or they'll get mismatch errors when joining.
Minecraft Java servers from $3.70/month on AMD EPYC with dedicated RAM. One-click Paper, Fabric, Forge and Modrinth modpacks, backups and SFTP included. Try one free for 48 hours, no card needed.