High school sophomore Vikas Prasad has one main goal: score a production placement with a major rap artist before the end of the school year. When he’s not in class, the 16-year-old spends most of his time making music in his bedroom in the suburbs of San Jose, California. Online, he’s part of a producer community that congregates around livestreams and beat marketplaces, hoping to learn the production trick or make the connection that will land them their big break.

Prasad first started messing around with production software about 18 months ago. Initially he attempted to replicate what he saw in beatmaking tutorials from producers like Nick Mira (“Lucid Dreams”) and KBeaZy (Kehlani’s “Toxic”). “I would practice every day trying to make beats,” he says. “Then I heard about loops, and I just started doing that.”

These loops are snippets of original music that Prasad composes at his computer, melodic ideas that might serve as the instrumental hook of a song—but without the rest of the song attached. They range in length and complexity: some incorporate one or two different sounds, while others are multi-layered miniature compositions. Every two weeks, he packages around 40 of his best loops to send to established producers he connected with on Instagram. If everything goes perfectly, a producer will use one of his loops in a beat—they might change the tempo, adjust the pitch, chop it up and rearrange it, or just drop it in as-is—and an artist will record a song over it.

In recent years, these melody loops, and the musicians who create them, have become a fundamental part of the way rap music is made. For up-and-comers like Prasad, supplying well-connected producers with packs of pre-made melodies has become the most effective method to get a foot in the industry’s door. And for producers working with prolific rappers, outsourcing the time-consuming work of writing a melody to a pool of dedicated loopmakers is the most efficient way to keep making hits.