I am working on a tax loss harvesting tracking and reminder app. For index funds in my taxable account, it tells me when there is a loss/savings opportunity th

I am working on a tax loss harvesting tracking and reminder app. For index funds in my taxable account, it tells me when there is a loss/savings opportunity that is over whatever threshold I give it. This way I get email reminders if there is an opportunity to save a few hundred or thousand dollars every time the market dips. This is a bit more versatile than just a reminder for certain prices because I am continually reinvesting at different cost basis.