Yes indexers are fine for this, but its hard to make core client features depend on single specialized servers which don’t have a spec. This is just asking for your app to stop working eventually. I try to avoid that as much as I can in damus.

People can also spam contact lists and fake the count (primal shows me as 1 million followers when it’s probably more like 200k), so i’m not sure if it will ever be accurate. I don’t like lying to users.