Modpack Checker

Modpack Checker

A lightweight Fabric mod for Minecraft servers to verify that clients are using the correct modpack version.

by
1.6K Downloads
fabricmanagement
Rent Server with this Mod

Screenshots

Client version is diferent from the server (Default message)
Client is missing the mod (Default message)

About this Mod

Modpack Checker

A lightweight Fabric mod to verify that players use the correct modpack version on your server.

Features

  • Simple version-based client-server check (no modlist comparison)
  • Automatic disconnect with helpful messages
  • Easy-to-edit TOML config files for both client and server
  • /reload support to apply changes without restarting
  • Dev mode: use version 0.0.0 to disable checks during development

How It Works

  1. Server sends a version check during login
  2. Client replies with the version from modpack-checker-client.toml
  3. Server compares it to its expected version
  4. If mismatched, the player is kicked with a custom message

Configuration

Server (config/modpack-checker-server.toml):

enable = true
expected_version = "1.0.0"
[messages]
no_mod = "Please install the Modpack: <your-modpack-link>"
wrong_version = "Please install modpack version {version}: <your-modpack-link+version>"
server_error = "Server configuration error. Please contact an administrator." 

Client (config/modpack-checker-client.toml):

version = "1.0.0"

Available Versions

0.1.2+1.20.xrelease
MC 1.20, 1.20.1, 1.20.2, 1.20.3, 1.20.4, 1.20.5, 1.20.6fabric
June 30, 2025
0.1.2+1.21.xrelease
MC 1.21, 1.21.1, 1.21.2, 1.21.3, 1.21.4, 1.21.5, 1.21.6, 1.21.7fabric
June 30, 2025
0.1.1release
MC 1.20.1fabric
June 30, 2025
0.1.0release
MC 1.20.1fabric
June 30, 2025

How to Install Modpack Checker on Your Server

1

Order Server

Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).

2

Set fabric Loader

In the panel under "Egg", select the fabric loader and matching Minecraft version (1.21.7).

3

Install Mod

Open the mod browser in the dashboard and search for "Modpack Checker". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.

Compatibility

Mod Loaders

fabric

Minecraft Versions

1.21.7, 1.21.6, 1.21.5 (+12 more)

Server-side

Required

Recommended RAM

4 GB(min. 3 GB)

Frequently Asked Questions

Modpack Checker server crashes on startup – what to do?

Most common cause: wrong fabric version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (1.21.7). You can switch loaders with one click in the panel.

Is Modpack Checker compatible with fabric?

Modpack Checker officially supports fabric for Minecraft 1.21.7, 1.21.6, 1.21.5. The Mado dashboard automatically detects incompatible loader combinations.

Server lagging with Modpack Checker – how to optimize performance?

Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Modpack Checker consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.

Rent Modded Server

Install Modpack Checker with just one click on your server.

Recommended RAM
4 GBab €8/mo
Min. 3 GB | +1 GB pro 8 Spieler
Create Server Now
1-Click Mod Install
NVMe SSD Storage
DDoS Protection included

Details

License
Apache License 2.0
Server-side
Required

Supported Versions

1.21.71.21.61.21.51.21.41.21.31.21.21.21.11.211.20.61.20.5+5 more