[eofster]

Absolutely! What exactly do you want to know? The rendering pipeline is the most standard one: Mapnik, Postgres, openstreetmap-carto, renderd. Everything is hosted on the own servers.

By resolution I mean exactly this - resolution. High-resolution tiles, also known as retina tiles. Low-resolution tiles are not used at all. All of that is not related to zoom.

If this wasn't clearly communicated by me: all zoom levels are rendered by the own servers.