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Darian Shirazi
General Partner · Gradient
Seed AI San Francisco, California
A self-taught engineer who was among Facebook's first, he backs AI developer tools such as Mastra, Linkup and Photon at the earliest stage.
Darian Shirazi taught himself to code and became one of Facebook's first engineers, reporting directly to Mark Zuckerberg. He later founded Radius, a B2B customer data company, and is now a general partner at Gradient who lives in San Francisco, California.
Leaving Berkeley to build Radius
He studied computer science and philosophy at the University of California, Berkeley, before leaving to work on startups full time. He was Radius's founder and CEO for more than seven years; the company raised more than $100 million and served dozens of Fortune 500 customers.
He was also an early investor in and adviser to Legora, Udemy, Palantir, Casetext and OpenGov.
Seed checks for AI developer tools
At Gradient his investments include Writer, Krea, Oura, Mastra, Linkup and Infisical. In 2026 he co-wrote Gradient's post on its investment in Photon, which lets developers run AI agents over messaging channels.
The firm's Fund 5 announcement, which he co-wrote with Zach Bratun-Glennon, says Gradient was founded "with a singular conviction: AI would be the greatest technological development of our lifetime."