One to grow on.
Digging around with etymology, trying to keep the text of my novel as properly 'contemporary' as possible, I've come across a small point. I'll skip the individual links; feel free to look these up.
Barkeeper starts from 1712; barkeep, not until 1846. Bartender, 1836. Mixologist, 1856. Barmaid, 1650s. Wench wasn't a barmaid, it was any young girl, especially if not married. An Innkeeper starts in the 1540s. Tapster has to be pre-15th century, since that's when the dictionary says they stopped making a distinction between a male tapper and a female tapper.
Server starts in the late 1300s. Alewife is probably better, runs at about the same time. But they're not called taverns until the late 1200s, which is way past a lot of worlds and most of the tropes associated with D&D armor and weapons. Comes from the French taverne, which is a shed made of boards, a booth or a stall. Latin is taberna, just in case anyone wants to know.
So the right term is anyone's guess. I'm going to go with Tapster. Just so the readers know, if your players enter a drinking house and want to talk to the bartender, you might let them know that your world doesn't take place in the Old West or Post-Napoleanic Europe. Unless it makes sense that they can sit down and drink with Karl Marx, Andrew Jackson or Charles Dickens.