LOS ANGELES >> Here’s a quick piece of pop trivia: What do Drake, Katy Perry, the Weeknd, Rihanna, Calvin Harris, Nicki Minaj, Big Sean, Halsey, Maroon 5, Travis Scott and Camila Cabello have in common?

The answer, in addition to big market share: melodies written by Starrah, perhaps the most ubiquitous force in music who also happens to be completely obscure.

An A-list studio presence for just two years, Starrah, 27, has tallied more than 6 billion streams on Spotify and YouTube alone — to say nothing of her innumerable radio plays — bridging genres and genders as a songwriter on “Fake Love” by Drake, “Needed Me” by Rihanna and “Havana,” Cabello’s breakout single, which peaked at No. 2 on the Billboard chart.

Yet anyone would be forgiven for not recognizing her name, let alone her face, which in images and videos is frequently animated and always obfuscated by a carefully placed hand, a K-pop-inspired panda mask or, if she happens to slip up and let a photographer capture her whole visage, an oversize emoji added after the fact.

“I like my privacy,” Starrah said with a believably shy grin at a recording studio in the San Fernando Valley earlier this month, at her first extensive interview. “The people I know who have fame would rather just take the money and leave the fame,” she said. “I still live my regular life.”

Even in an industry known for its shadowy influences, the vocalist born Brittany Hazzard stands out for her anonymity and the improbability of her rise.

Raised in a tiny Delaware beach town, the youngest of nine siblings, Starrah cut her path through urban radio, crafting indelible, rap-sung hooks for strivers like Kid Ink and Dej Loaf (“Be Real”), Kevin Gates (“2 Phones”) 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 percent this year — and hip-hop/R&B easily outpacing any other genre, the Katy Perrys and Maroon 5s of the world needed an emissary.

“I used to be told, ‘She’s too urban for these studio sessions,’” Nick Jarjour, Starrah’s manager, said in an interview. But with the trends moving in one direction — cemented by No. 1 hits like “Bad and Boujee” by Migos and “Bodak Yellow (Money Moves)” by Cardi B — “The industry started to realize that she’s not one-dimensional,” Jarjour said.

Starrah’s sharp rise has also coincided with increased awareness from everyday fans of the sausage-making process. While liner notes were once the domain of obsessive record nerds, the internet has pulled back the curtain and democratized fame for stalwart behind-the-scenes creators — songwriters have Instagram accounts, too, after all. Starrah recalled following the studio work of The-Dream, Ester Dean, James Fauntleroy and Frank Ocean (then known as Lonny Breaux) on blogs as a teenager and coveting their credits more than the spotlight.

As the allure of Svengali-type songwriters like Dr. Luke and Max Martin has fallen out of fashion (if not out of radio rotation), a crop of young female polymaths, including Julia Michaels, Charli XCX and Emily Warren, has grown. Rather than muting their personalities, these songwriters-slash-performers lend cred and rougher edges in addition to catchy choruses.

For Starrah, who is gay and can sing as well as she can rap, 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 hella wealthy.”

She attended Delaware State University, and became the first in her family to graduate. But on one early track, she sings of “PTSD from my childhood,” a SWAT team kicking down the door.

“I’ve seen both sides of the coin,” she said.

Initially inspired by street literature like Sister Souljah’s “The Coldest Winter Ever” and female rappers like Eve and Nicki Minaj — hence her dexterity with syncopated flows and finding unobvious rhythmic pockets in a beat — Starrah also developed the omnivorous taste of the playlist generation. For some of her earliest compositions, she found acoustic covers of songs like “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 first caught the ear of Jarjour online.

“I didn’t know if she was a girl or a boy, 11 years old or 27 years old,” he said, recalling the distinctiveness of her cadences. “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 now-deleted songs to SoundCloud and selling hook demos for $150 on Instagram. Jarjour was impressed by her work ethic, both out of the studio and in it: “From the beginning, Starrah sent more music than anyone else,” he said, and she was very organized, a rarity for prolific songwriters.

Gregarious, wide-eyed and relentlessly positive, Jarjour, 31, was also a complement for Starrah’s sheepish humility, and he quickly became her protector and champion. Though her reticence toward fame has lent her career a marketable mystique, “It’s not a gimmick,” Jarjour said. “She’s not thirsty.”

While social anxiety may keep her from award shows and meetings with label execs, her modesty and introvert’s knack for listening have made her a favorite of today’s superstars.

“Starrah is the secret Dr. Phil of the music industry,” Jarjour said.

Starrah said she now looks at many of the artists she writes for “like they’re my family,” but she’s also a student of their sounds and personas.

“As a fan, I know where I want their music to go,” she said.

“I definitely creep” on social media, Starrah added, and said she reads gossip blogs for fodder.

“Even though a lot of people say ‘blogs aren’t true,’ what’s said on the blogs still affects that person — period.”

She recalled Rihanna gushing over the steely breakup jam “Needed Me” — with its Instagrammable one-liners like “Didn’t they tell you that I was a savage?” — 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. Though she had previously specialized in the cross-section of club and critical favorites that became unexpectedly durable hits (“Pass Dat” by Jeremih, “Body” by Dreezy), her work on tracks like Katy Perry’s “Swish Swish,” Halsey’s “Now or Never” and Calvin 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, ever,” said 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.”

Producer Diplo said in an email: “Hip-hop is the language right now, but Starrah is comfortable applying that to every genre.” He added that the pair had indeed worked on country records together.

Starrah has also flirted with delivering her own songs, quietly releasing an EP with Diplo in September (as a cartoon avatar), though ironically, the omnipresence of her sound left her own sticky tracks sounding a bit generic.

Still, she is enjoying the spoils of her hits — she recently toured a $3.4 million home in the Los Angeles area in what the listing described as a “highly desirable celebrity neighborhood” — along with the perks of obscurity.

“I love my day to day,” Starrah said. “I don’t want it to be crowded, or to ever affect me going home, being with my family, taking my nieces bowling or to the skating rink.”

The next afternoon, she was back in the studio, as if it were any other day job. While producers Jason Evigan — with whom Starrah wrote Maroon 5’s recent Top 10 hit “What Lovers Do” — and Cirkut plinked around with a moody ’80s synth line, Starrah sat silently in a corner, tapping lyrics into her phone.

(While many modern songwriters — from Migos to Sia to Ed Sheeran — tend to start with melodies, using gibberish as lyrics and then fit words in retroactively, Starrah writes lyrics first and then molds them to the production.)

After barely 10 minutes of hearing the looped riff, she stood up: “Ready?”

Cirkut laughed.

“She out-wrote the beat,” he said, rushing to finish his part as Starrah made her way to the darkened vocal booth.

What she delivered, filtered through Auto-Tune, was a rush of tangled syllables and rat-a-tat repetition that somehow sounded familiar and was instantly hummable. In another half an hour, she had a first verse, chorus and post-chorus down, and she left the microphone to write some more. Jarjour estimated that Starrah had up to 800 such sketches.

She paced the room searching for more inspiration, but not too hard. In an imperceptible instant, she decided it just wasn’t happening that afternoon, exchanged a few pleasantries with her producers and was gone. Just as easily as she’d conjured future radio catnip, Starrah had clocked out.