Jamal Edwards has died aged 31, his company has told media.
The YouTuber was the founder of SBTV, an online music platform that helped launch the careers of Dave, Ed Sheeran and Jessie J.
He was vital to some of the country's most popular artists reaching their audience and becoming household names.
Since news of his death was announced, friends and collaborators have shared their condolences on social media.
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AJ Tracey tweeted: "RIP Jamal Edwards, west London legend status."
Sharing a photo of Jamal, another wrote: "This man did so much for grime and UK music. I grew up watching SBTV to see all the underrepresented artists of the scene. His grind is unmatched. A real inspiration and a huge, huge loss to the industry.
"Honoured to share first names with you.
"RIP Jamal Edwards."
George the Poet wrote: "RIP Jamal Edwards. Giving God thanks that you did what he sent you to do. So many of us owe our careers to you bro. Thank you for everything."
Amelia Dimoldenmerg said: "Jamal Edwards, one of the most generous people I have ever met. Someone who loved music and truly believed in all the joy it brings.
"Going above and beyond to connect people and bring ideas to life. You have shaped culture and changed the lives of others - never to be forgotten."
"Just heard the news. Absolutely heartbroken," wrote MistaJam.
"Jamal Edwards was a one of a kind. A trailblazer, a pioneer, a beacon, a genius. Sending love and prayers to his family. He will truly be missed.
"God Bless you Jamal Edwards."
Munya Chawawa said: "Rest in Peace, Jamal Edwards.
"To think how many dreams were fulfilled and how much potential was discovered because of your platform and work.
"What an incredible legacy; thank you."
Speaking to the BBC in 2013, Jamal said the aim behind sharing artists to YouTube was to enable other friends to see them.
He told the channel: "You can say my videos had mixed reviews to begin with, some people didn't get them, but others thought they were sick [good].
"So I started to put them up on YouTube so everyone could see them, and it just grew from there."
No details around Jamal's death have yet been released.
Dominic Smithers