Official release: SMB4 League Import Tool for PC (I built it, here’s the GitHub + details)

Hey everyone, so as the dev behind the SMB4 League Import Tool (LIT), I figured after a week of iterating and updating on MVPMods (it was announced here way ahead of time when I just wanted something functional and the UI wasn't as polished) to make the release official now that the GitHub repo, documentation, and issue tracking are live. I rebuilt the tool from scratch and constantly poked for feedback

A lot of people have been creating and sharing custom leagues and franchises in SMB4, but getting them to actually show up in your own SMB4 save has required having to swap whole save folders, and that was always a cumbersome experience.

So I built this special utility that cleans up that entire process and modifies your save to let outside leagues/franchises coexist with what you have in your own little/massive SMB4 universe.

I wanted something reliable that didn’t require anyone to poke around SQLite files or hex editors and could work at best 99% of the time, every time. If this helps streamline the custom league scene even a little bit, mission accomplished. It's 100% free to download and use.

Just a quick breakdown:

What the tool does

• Automatically remembers your SMB4 save directory on opening
• Loads master.sav and all league-*.sav files in the same folder
• Shows which leagues/franchises are registered vs unregistered
• Lets you register/unregister with a single checkbox
• Preserves correct ordering (Default, Custom, then Franchise)
• Writes back a clean, valid master.sav
• Self-contained .exe (no dependencies)
• Cleans up temporary files on exit

Basically, if someone shares a custom league with you (or you make several yourself), this tool plugs them safely into your save.

Download + Source Code (GitHub)

GitHub: https://github.com/firstbaseman/smb4-league-import-tool

It's Windows native, but as a pleasant surprise, Linux/Steamdeck users can run it under Wine.

I'll say that the tool is feature-complete so I’ll be maintaining UI quirks and bugs only if they come up.

Let's properly share some leagues with the homies.

Happy modding!