Those who loved using read-wise but hate paying 4$ every month for it, obsidian has a plugin that does just that: https://github.com/hadynz/obsidian-kindle-plugin Combined with one of the many flashcard plugins, it replicates the exact same experience of readwise for free.

Quite nice if someone is using readwise just for kindle. But readwise supports a host of inbound connections. The ones I use for example are - Kindle, command browser for ipad, pocket, twitter, hypothesis plugin for Chrome. These ensure I have a way to capture highlights/notes from almost every reading source of mine.