I don't know how Kagi manages it. I suspect like duckduckgo, they index a little bit on their own, and use a GBY [1] as a back up. According to Seirdy[1], they

I don't know how Kagi manages it. I suspect like duckduckgo, they index a little bit on their own, and use a GBY [1] as a back up. According to Seirdy[1], they use Brave in the background. Brave just burn their cryptomoney to build a search engine. Don't get me wrong, I like what their doing, but it was easy for them to start since they bootstraped from Cliqz' index[2] And for the second part, you do need to store the relationship between keywords and pages, that's what I was talking about. You cannot store a relationship between "types of water" and "reddit.com" you need to store it between "type of water" and "reddit.com/r/hydrohomies/..." [1] https://seirdy.one/posts/2021/03/10/search-engines-with-own-indexes/ https://seirdy.one/posts/2021/03/10/search-engines-with-own-... [2] https://brave.com/blog/brave-search/ https://brave.com/blog/brave-search/