I'm not sure how to advertise the supported NIP-50 modifiers yet, there's no NIP-11 field for that afaik. Currently there are these ones that may be freely mixed: is:popular (from popular pubkeys), is:rising (from those almost reaching popular status), is:spam, include:spam, sort:top (sort content by highest engagement), language:xx. On REQs you just add an extra "search" field to the filter, e.g.: `{ "kinds": [1], "search": "sort:top language:es language:fr" }` Or use a custom wss url so that you don't need to add the "search" field to the filter.