[vlz]

Cool, have been searching for something like this.

Small suggestion: would put on the page what the name abbreviates. Or is "When are you free" so universal? (I didn't get it before seeing your post, but am not a native speaker). Also do you pronounce it like "wife" or like "waive"?

[chrisweekly]

As a native English speaker (online for decades), I can confirm "WAYF" is not a universally-recognized acronym. I'd pronounce it "waif" (which is not quite archaic, but a relatively rarely-used word).

[frederikbmm]

WAYF could also be "where are your from". At least in Denmark (https://www.wayf.dk/).