LOS ANGELES • What do Drake, The Weeknd, Rihanna, Calvin Harris, Nicki Minaj, Big Sean, Halsey and Camila Cabello have in common?
The answer - melodies written by Starrah, who also happens to be completely obscure.
An A-list studio presence for just two years, the 27-year-old has tallied more than six billion streams on Spotify and YouTube alone - to say nothing of her innumerable radio plays - bridging genres as a songwriter on Fake Love by Drake, Needed Me by Rihanna and Havana, Cabello's breakout single.
Yet, anyone would be forgiven for not recognising her name, let alone her face, which, in images and videos, is frequently animated and always obfuscated by a carefully placed hand or a K-pop-inspired panda mask.
"I like my privacy," Starrah said. "I still live my regular life."
Raised in a Delaware beach town, the youngest of nine siblings cut her path through urban radio, crafting rap-sung hooks for strivers such as Kid Ink and Dej Loaf (Be Real) and Travis Scott and Young Thug (Pick Up The Phone) before making the all-but-unheard-of crossover to the overwhelmingly white echelons of Top 40.
"She's brought urban music into pop," said producer Cirkut, known for his work with The Weeknd and Miley Cyrus.
Somebody had to do it. With streaming now the top mode of listener consumption by far - up nearly 60 per cent this year - and hip-hop/R&B easily outpacing any other genre, the Katy Perrys and Maroon 5s needed a helping hand.
For Starrah, code-switching while remaining authentic to herself has always come easily. "I grew up in the ghetto," she said. "But around me, it was like a gilded curtain - everyone else was wealthy."
She attended Delaware State University and became the first in her family to graduate. But on one early track, she sings of a police team kicking down the door. "I've seen both sides of the coin," she said.
Initially inspired by street literature such as Sister Souljah's The Coldest Winter Ever and female rappers such as Eve and Minaj, Starrah also developed the omnivorous taste of the playlist generation.
For some of her earliest compositions, she found acoustic covers of songs such as Yellow by Coldplay and improvised on top of them.
It was one such track, titled Drank Up, which sampled the electronic song, About You by XXYYXX, that caught the ear of Mr Nick Jarjour, who is now her manager.
"I didn't know if she was a girl or a boy, 11 years old or 27 years old," he said. "She was the most ambiguous person I'd ever heard."
Starrah had moved to Los Angeles after college and was working at Urban Outfitters and Public Storage while pursuing music, posting songs to SoundCloud and selling hook demos for US$150 (S$200) on Instagram.
Gregarious and relentlessly positive, Mr Jarjour, 31, was also a complement for Starrah's humility, and quickly became her protector and champion.
Although her reticence towards fame has lent her career a marketable mystique, "it's not a gimmick", he said. "She's not thirsty."
While social anxiety may keep her from award shows and meetings with executives, her modesty has made her a favourite of superstars.
Starrah said she now looks at many of the artists she writes for "like they're my family", but she is also a student of their sounds and personas. "As a fan, I know where I want their music to go," she added.
She recalled Rihanna gushing over the steely break-up jam Needed Me, which peaked at No. 7 last year and went on to become the singer's longest-charting hit.
This year, having proven her Billboard viability, Starrah focused on expansion.
Although she had previously specialised in the cross-section of club and critical favourites that became unexpectedly durable hits (Pass Dat by Jeremih, Body by Dreezy), her work on tracks such as Perry's Swish Swish, Halsey's Now Or Never and Harris' Feels were more naked appeals to pop dominance.
And while not quite critically adored smashes, such songs may prove effective in Starrah's effort to stay unpredictable.
"She doesn't want to be pigeonholed," said Ms Ashley Calhoun of Pulse Music Group, who signed Starrah to a publishing contract as a songwriter in 2015.
"If she wants to write a country hit, I have no doubt she can do that."