The title was confirmed by co-writer and producer Penguin Prison in an interview in 2011. Penguin Prison had also worked on a remix of the song "Blue Jeans" and later "Blue Velvet". The producer confirmed the song was about Del Rey's BlackBerry Messenger.
Two snippets of the song's final version leaked on May 10 and July 4, 2016. On August 15, 2016, a demo of the song leaked, with the original file containing metadata that said "BBM Baby (4-14-11)", which suggests the song was recorded on April 14, 2011.
An edited final version with heavier production leaked on December 25, 2016.
The lyric "I heart you, you're the one that I adore" is similar to "I heart you and I wanna be your girl" from "Big Bad Wolf".
Del Rey singing "XO" is similar to "St. Tropez", wherein she sings "XXO".