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


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
/reloadsupport to apply changes without restarting- Dev mode: use version
0.0.0to disable checks during development
How It Works
- Server sends a version check during login
- Client replies with the version from
modpack-checker-client.toml - Server compares it to its expected version
- 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
How to Install Modpack Checker on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set fabric Loader
In the panel under "Egg", select the fabric loader and matching Minecraft version (1.21.7).
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
Minecraft Versions
1.21.7, 1.21.6, 1.21.5 (+12 more)
Server-side
✓ RequiredRecommended 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.
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Rent Modded Server
Install Modpack Checker with just one click on your server.