Editor's note: Chromatik is one of Inc.'s 2015 30 Under 30. This year's readers' choice winner is ThinkLite.  

Even before McSweeney's publishing house released Beck Hansen's 2012 album Song Reader as individual pieces of sheet music, procuring sheet music has been an important--if vexing--pursuit for musicians. 

Matt Sandler wants to change all that. In 2014, the UCLA-educated saxophone player launched Chromatik with the goal of modernizing how people access music education tools. In essence, he wants to do for sheet music what Spotify did for streaming music.

"We saw an interesting way to bring how people practice, learn, and perform music into the digital age by using any mobile device as a conduit for learning, performing, and playing music," Sandler says.

So far, the company, which offers a free iOS application and a digital catalog of more than 30,000 titles, from the Beatles to Disney's Frozen, has gained impressive uptake since launching in 2011. Not only have entertainers Will Smith and Bruno Mars invested in the company, prominent investment firms, including Rustic Canyon Partners and 500 Startups, have helped bring Chromatik's funding tally up to $6.7 million.

"I'm just a silly musician, so trying to navigate how to finance a huge operation like this was certainly bewildering at the beginning," Sandler says.

Silly or not, Chromatik is making big waves in the music industry. While still technically in beta in 2012, Chromatik snagged a deal with American Idol when the hit Fox show's house band scrapped its paper sheet music in favor of the Chromatik iPad app during rehearsals and live shows.

The company has also featured exclusives with some of the world's biggest artists, including Queen, Linkin Park, Alison Krauss, and Grouplove. Each title is available for more than 20 instruments, with hundreds of new titles added each week, according to Sandler. And if a title doesn't exist yet, Chromatik's team of musicians just makes one from scratch. Chromatik's YouTube channel has logged nearly 10 million views to date. 

It's figures like these that have industry watchers intrigued. "The market for printed music is tiny ... but in the longer term, like Pandora, this could be a clandestine search company," says Richard Tullo, an analyst at Albert Fried & Company, who covers Pandora.

Big data aspirations aside--for now at least--Chromatik lets users upload, download, and annotate their own sheet music. The company also encourages musicians to teach one another and track their progress by recording their own performances and sharing them on YouTube, Facebook, Twitter, or the "Chromatik Stage," a platform for sharing audio or video clips with other users. The app also comes bundled with a built-in metronome, tuner, and practice log--all essential tools for musicians of any skill level. Users can even watch music videos on YouTube that sync along with the actual sheet music.

"One-half of the equation is, how do people listen to music?" Sandler says. "The other half of the mobile music equation is, how do people play, learn, and share music they love?"

This is the key to Chromatik's business model, adds Sandler. Much like Spotify, Chromatik works off a freemium model supported largely by advertising. The team plans to monetize the service by introducing, in the near future, Chromatik Premium, though the company's idea of what that might include is still in the works. For now, users can enjoy the app--and its recently released Android offering--at no charge. Though Chromatik wouldn't disclose revenue figures, Sandler maintains the service is quickly becoming one of the fastest-growing and most widely used music apps in the world. 

And maybe they'll find sustainable success, too, suggests Tullo, who cautions the company against trying to grow too quickly. "If they don't screw it up by doing only what Silicon Valley wants them to do, it could be a really nice business," he says.