My brain is terrible at visualizing and tracking how various concepts fit together. Excalidraw helps make my brain be better. It’s a free low-fidelity whiteboarding tool that I’ve been using for system design interviews, brainstorming, flow diagrams, wireframe/mockups. Anything that I used to draw on a piece of paper is now being done in Excalidraw. It has basically everything you need to diagram, and if you need more, there is a plugin library to get extra shapes.
The low fidelity look and feel reduces the friction of creating diagrams. I don’t need to worry about perfection, I can slap together a few shapes add some text, and I’ve mapped out what was in my head.
Here are a couple of random things I’ve made in Excalidraw:
Flow chart of how my personal website is structured
Brainstorming a side project I’m working on