Oh man, this is actually exactly something I want. I want to invest in the s&p 500, like an index etf, but I want to filter out companies which I don't agree with ethically. I also want to look at my custom index's performance historically so I can see how well it tracks the overall market.

It is extremely hard to actually do this. There's a plethora of hurdles in the way - you need to get data (I bought some historical s&p 500 data, seemed to be the only way), and then you need to figure out what to do with it too. When you look at a graph on the index, what is that based on? Do they rebalance every day? Monthly? Who knows? I was never able to reconstruct an s&p 500 graph from source data myself as a baseline.

I will definitely be giving this a try.

EDIT: signed up for the waitlist!

Also, a question: Can you use this without some sort of linked broker account? IE, you tell it what you've got, and it spits out instructions that you execute manually? I ask because I'm in Europe, and only the big American brokers ever seem to get proper integrations with anything.