This is pretty much exactly what I have been looking for, I do this with paper/pencil on our fridge.

If you don't open-source it, where is the data stored?

Right now just unmanaged postgres instance hosted on fly.io

The real question is: does your wife use it? I have an excel budget that I updated based on our real spending habits every couple months. I also use projectifi for the long term asset planning, using the budget as an input for our surplus cash.

My wife has never opened either and has vague anxiety (read: frustrating) about going on vacations or making big purchases even though we’re doing great. I’m the sole income for 5 so I suppose I have to take the mental load of ensuring things are budgeted, diversified, HSA/529 is funded etc.

Yes, she does! She checks it everyday and she loves the simplicity of it.

I also tried the spreadsheet approach since I was so frustrated with budgeting apps, but they're a bit overwhelming for some.

This looks like a great tool. Not sure what the crystal ball does.

Thanks for the feedback, it's like a forecasting feature. Say you want to spend over budget today, you can see how that changes your daily budget 1 day, 2 days, 3 days, etc. out from today. Or let's say you plan on being frugal for the next few days and will spend only $20.00 over the next 3 days, by the 4th day your daily budget will adjust accordingly: https://imgur.com/a/hD9R2zv

What a great feature! I also had no idea what it meant so for UI/UX reasons I'd add some alt-text explaining that.