For work, I often use Sourcetree as my UI for dealing with BitBucket.

I’ve been using WinMerge for more years than I can count.

You can setup WinMerge as the Diff tool really easily in Sourcetree. Just pick it in the settings. :)

But, if you want to use WinMerge as your Merge tool, you need to set Custom settings.

External Diff Tool: WinMerge
Diff Command: C:\Program Files (x86)\WinMerge\WinMergeU.exe
Arguments: \”$LOCAL\” \”$REMOTE\”

Merge Tool: Custom
Merge Command: C:\Program Files (x86)\WinMerge\WinMergeU.exe
Arguments: -wl -wm -dl PreviousVersion -dm Base -dr Local $LOCAL $BASE $REMOTE -o $MERGED