They do have their own crawler and I believe supplement from bing only when necessary. Something like 98% of results are from their own index across all users. They actually have a breakdown for every search.
I think they actually have the largest independent index outside of Google/Bing right now.
Others that exclusively use their own index are:
Mojeek (results aren’t great)
Kagi (result are pretty good imo)
They do have their own crawler and I believe supplement from bing only when necessary. Something like 98% of results are from their own index across all users. They actually have a breakdown for every search.
I think they actually have the largest independent index outside of Google/Bing right now.
Others that exclusively use their own index are:
Mojeek (results aren’t great)
Kagi (result are pretty good imo)