I use the query “/data/wow/connected-realm/{connectedRealmId}/auctions”, as indicated in the official documentation. In response, a collection of all items is sent. How can I get data about a certain subject? And is it possible to get items of a certain category?
No, this endpoint exposes an hourly generated snapshot of all active auctions on the connected realm.
Do I understand correctly that I will not be able to find a legendary item of a certain item level in this way? Will I only be able to get the quantity of the item being sold without taking it into account?
Yes, if you want to use the API to fetch only those. You can, however, filter the desired items on your side after fetching the snapshot.
Item level and other variants (sockets, bonus attributes, etc) can be sorted out by comparing the bonus ids, context, etc
But I didn’t see this data in the json file that the api sends me