Gitkraken can use the Git Config Default merge and diff tool. This allows you to right click a file and "open external diff tool". I like meld the best for this. This works for git command line and should work for more than just GitKraken.

GitKrakenMeldWindows10.md

First, Download and install the newest version of Meld for Windows. https://download.gnome.org/binaries/win32/meld/

Next we need to edit your .gitconfig file. This file lives as a hidden file in your user directory. Here is a sample of mine:

[user]
	email = me@email.com
	name = Sir Kuttin
[merge]
	tool = meld
[diff]
	tool = meld
[mergetool "meld"]
	path = C:\\Program Files (x86)\\Meld\\Meld.exe
	cmd = \"C:/Program Files (x86)/Meld/Meld.exe\" --diff \"$BASE\" \"$LOCAL\" \"$REMOTE\" --output \"$MERGED\"

Once this is done, you can go to Gitkraken's Preferences and set up the merge and diff tool to use the GitConfig Default. This also allows meld to be used for git command line and should also work with other Git GUIs.

Excellent! Worked perfectly, thanks!!

Worked!

Does not work for me. Fresh install of GitKraken

• OS: Windows 10 Education 21H2 19044.1586

worked perfectly for me.
configured CompareIt! tool as follows:

[diff]
	tool=wincmp3
[difftool "wincmp3"]
    cmd = \"C:\\Program Files (x86)\\Compare It!\\wincmp3.exe\" \"$REMOTE\" \"$LOCAL\"
	trustExitCode = true

Not sure if the trustExitCode = true is necessary tbh. But got that from other places.

what if Linux OS and meld diff tool installed with flatpak (command is flatpak run org.gnome.meld) ?