They are both bl but shounen ai is lighter maybe only until kissing and stuff, but yaoi is more hardcore like it contains erotic things too
Yaoi has sex and shounen ai doesn't
Yaoi = shown sex scenes in the comic
Shounen ai = more focus on the romance (at least in most cases) and no sex scenes in the comic itself (though they may be implied)
Well, in short, Yaoi would lead to sex scenes, nudity, etc while Shounen Ai usually focus on development of romantic relationship and the hottest scene you'll get is only a tender kiss on the lip lol
What’s the difference between yaoi and shounen ai???