Download

Download modcheck

Find out which mods are ready before you upgrade the server — not after it refuses to start.

Want the smallest possible footprint? Take the command line. Want to click a few times? Take the desktop app. Both read the same config and the same profile, so you can switch whenever you like.

Choose

Choose your download

Both run the same verdict code. What differs is the size, and how you drive it.

CLI standalone

Smallest

modcheck--cli-standalone.zip

Size: About 18 MB, unpacked into a portable folder
Dependencies: None beyond the Python standard library
Best for: Scripting it, wiring it into CI, or a server with no desktop environment
How to start: Unzip, then run 启动CLI.cmd
Uninstall: Delete the folder

Portable and green: config and profiles live in the config folder right beside it.

Desktop app

Least friction

modcheck--gui.zip

Size: About 70 MB, most of it Qt
Dependencies: PyQt6 — already bundled, nothing for you to install
Best for: Clicking a few times and reading a table
How to start: Unzip first, then run 启动GUI.cmd
Heads up: You must extract it; the exe will not run on its own

Reads the same config and the same profiles as the CLI.

Mod downloads

It does not just tell you — it fetches them

Once the check is done, pull down every version it recommended in one go, instead of opening thirty project pages by hand.

This is the slowest part of preparing an upgrade

For a 30-mod server, doing it by hand means thirty release pages, working out stable versus beta, checking each file against your loader and game version, and dodging the ones that look newest but will not run. modcheck already made those calls during the check — the download just acts on them.

How to trigger it

Desktop app: after a check finishes, click "Download recommended versions…". Click it before running a check and it will ask you to run one first — it will not guess.
Command line: after a check, pick "Download recommended versions" from the menu.
It only downloads the recommended build for Ready and Check rows. Beta only is skipped entirely, and Blocked has nothing to download.

The judgement it saves you

Primary file only: it takes the .jar Modrinth marks as primary; sources and javadoc jars are not downloaded (it tells you in the summary if any mod has extra files).
No betas handed to you: no snapshots, no alpha or beta builds. If you want betas counted, you turn on --pre yourself during the check.
Official links only: files come from Modrinth's own CDN. This project never re-hosts or redistributes mod files.

It still never touches your mods folder

A download only happens because you clicked, and it only writes into a folder you chose. New builds land somewhere separate; whether and when to swap them in stays your call — which is also why it does not overwrite files of the same name without asking.

Environment

System requirements

The packaged builds run as they are — no runtime to install first.

What modcheck needs to run
Item	Requirement
Operating system	Windows 10 or newer; Linux
Python	Not needed for the packaged builds. Python 3.11+ is only required if you run from source
Extra requirement, desktop app	None — PyQt6 ships inside the build
Disk usage	About 18 MB for the CLI; about 70 MB for the desktop app once extracted
Network	Required. Identification and verdicts query Modrinth, CurseForge and Mojang's official version manifest
Permissions	Read access to your mods folder — nothing written, modified or deleted

Licence

Source and licence

modcheck is released under GPL-3.0. Use it, modify it, redistribute it — as long as your modified version stays open under the same licence.

The desktop app uses PyQt6, which is itself licensed GPL v3. The command line build has zero third-party dependencies and is not affected by that. If GPL does not fit your distribution plans, the gui front end can be swapped for PySide6 (LGPL) — the verdict logic lives in core and does not change.

Source entry points:

GitHub repository Download the source archive All releases

Safety

Verification and safety

Download only from this project's Releases page. There are no mirror downloads and no third-party installer; an installer you find elsewhere is not ours.
The tool does not redistribute mod files. It only looks up version data. Mods themselves come from Modrinth's official CDN, or wherever you already get them.
The version is part of the file name. Glancing at it before you download rules out most cases of grabbing the wrong build.

Limits

Known limitations

Better to know these now than halfway through.

It needs a network. Verdicts query the public Modrinth API, CurseForge and Mojang's official version manifest.
Offline, it can only use what is inside the jar. It can read file names and embedded metadata, but it cannot see which mod version supports which game version — so almost everything will come back Undetermined.
No snapshot version checking. Verdicts target release versions only.
No recursive dependency resolution. It checks what is in the profile, not what those mods depend on.
A mod the platforms have not indexed can only come back Undetermined. It will not guess a version for you.

Downloaded it. What now?

The three-minute walkthrough takes you from the mods folder to a verdict, and tells you what each step should look like.

Get started It downloads the mods too