That being said, it's only anachronistic if your setting is this world. No reason why the equivalent of an inn wouldn't be serving a stimulant beverage of some kind.
Certainly coffee houses do have historic basis in our own reality but the highly commercialized omnipresent franchises with extensive supply chains like IRL Starbucks would definitely be a bit more anachronistic, especially in an adveture friendly world where monsters and bandits are waiting outside the walls of the city waiting to ambush cargo shipments.
Something like that probably wouldn't have been even remotely possible until the age of Mercantilism well after the medieval period gave way to the Renaissance and eventually the age of exploration.
Depends on the magic. Fireball was used in the seventh through fourteenth centuries, so that's not anachronistic. But if you want to do elemental transmutation, that wasn't discovered until 1896. You could have it in steampunk.
Fair point! I'm not saying it's a bad thing, it's just interesting to me cause I'm not used to it. I usually run D&D as medieval (like ~1300 AD) European fantasy with magic and a little bit of anachronistic renaissance stuff.