If you want to move beyond the basic web maker, the modding community suggests: Visual Studio Code with "HOI4 Mod Utilities":
: Often used by veterans to map out the logic and flow (prerequisites, mutual exclusions) of a tree before any actual coding begins. 💡 Pro-Tips for Successful Trees hoi4 focus tree maker
Which focuses must be finished first? This creates the "lines" connecting the tree. Mutually Exclusive: If you want to move beyond the basic