Travis Scott got a huge bday shoutout from Kylie Friday in the form of a billboard on the corner of one of the busiest intersections in West Hollywood -- Santa Monica and La Cienega.

The billboard features a huge headshot of their 1-year-old daughter along with another pic of her and Mom, with the message ... "Happy Birthday Daddy." It's signed, "Love, Mommy & Stormi XO."

As if this was not enough, Kylie also threw Travis an 'Avengers'-themed bash Thursday night, which included a private screening for 'Endgame.'

Scott's actual birthday isn't until Tuesday, April 30 ... but who is keeping track? He'll be 28.

BTW -- Travis' bday billboard is directly across the street from another one with a giant face on it ... Taylor Swift's. As we reported ... she's got something important she want's to advertise, as well.