Behave started as a spreadsheet I kept for years — every card, every 401k loan, every savings pod, tracked by hand so I could actually see progress instead of just feeling anxious about it. It worked, until keeping it updated became its own chore, and I let it die.
This is that spreadsheet, rebuilt properly: real interest math instead of a rough guess, history that logs itself the moment you save, and a dashboard honest enough about where you stand that you'll actually want to open it.
I still run my own numbers through this every day. It's not a side project I built and walked away from — it's maintained because I use it, and I keep improving it because I want it to be worth what it costs.