[gnicholas]

Check out Diffit, which takes URLs or text and re-levels the text and gives comprehension questions. [1]

Also check out Quill, which is a nonprofit mostly focused on writing but moving into the reading comprehension area as well. [2]

There are others as well, but it's not clear which will emerge as winners.

1: https://app.diffit.me/

2: https://www.quill.org/