Cardi B Throws Private Party for Birthday, No Offset but Lots of 'Cake'

Cardi B's making sure her 32nd birthday is memorable ... for herself, for everyone watching her ass-shaking celebration and, possibly, for her estranged hubby who did not see the party in person.

The private party went down Saturday night in Manhattan, with Cardi labeling her shindig, "Bardi in the City" -- although it looked more like Bardi Barely Covered!

Cardi was rocking a backless black romper that showed off all her back tatts, and struggled to cover her ass. The tiny outfit didn't hamper her signature dance moves ... as she twerked all night for the cameras, and was even slinging drinks, at one point in the evening.

As the birthday girl/bartender put it, "Free shots for everyone on the floor!"

Cardi's sister Hennessy made an appearance, but, notably, Offset was not in the crowd.

Remember, last time we saw Cardi out clubbing in NYC, her ex surprised everyone by showing up at the venue -- and, although they had no contact that night, it fueled some speculation he might try to get back with her.

Let's just say ... if that were the case, surprising Cardi at her birthday bash is just the kinda move Offset would've pulled during their past breakups.

The fact he was MIA for Saturday night's festivities tells ya ... this time the divorce seems to be sticking. Sooo ... happy birthday???