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For Denis Yarats (Courant), what began as a Ph.D. project at NYU became the foundation of one of today’s fastest-growing AI startups.
“Sometimes it feels incredibly impossible, but you just do it one day at a time and see what happens,” he said.
Guided by a belief that knowledge should be both accurate and accessible, Yarats built Perplexity — a fast, trustworthy “answer engine” designed to bridge the gap between academic precision and human curiosity in an age of information overload.
From Papers to a Company
During the 2020 pandemic lockdowns, Yarats co-authored a research paper on reinforcement learning from human feedback. Just two days later, Aravind Srinivas, then a Ph.D. student at Berkeley, published a paper with an almost identical idea.
“It’s funny — that’s how we started talking and collaborating,” Yarats recalled, reflecting on how academia responded to the rise of AI. “For the average person, the inflection point was the ChatGPT moment. For researchers, it was a steady acceleration visible years earlier.”
That coincidence planted the seed of a partnership. The two exchanged ideas throughout the pandemic, staying in touch even as Srinivas joined OpenAI a year later. When large language models began to show new potential, they decided to seize the opportunity.
By the summer of 2022, they formally launched Perplexity — just a week after ChatGPT.
Building an Answer Engine
In a crowded market of AI startups, Yarats remains grounded in his commitment to research and rigor.
“In academia, you always cite your sources,” Yarats said. “We brought that same principle to Perplexity: facts should be traceable, just like citations and an H-index.”
While early language models often “hallucinated” false information, Perplexity ensures every answer comes with verifiable references.
Even the company’s name reflects its academic roots. “Perplexity is what we worked on every day as Ph.D. students,” Yarats explained. “It’s the synonym of entropy — the uncertainty — you’re always trying to reduce.”
Blending Academia and Startup Culture
With roots in research, Yarats emphasizes that while Perplexity has developed the structure of a traditional tech startup, it still operates like a lab — combining the best of both worlds.
His teams remain intentionally small, never more than five people per project, to focus on solving real problems rather than managing coordination. The setup mirrors the philosophy of doctoral research, where progress depends on rapid experimentation balanced by the patience and determination for a result.
Despite leaving his degree unfinished, Yarats feels little has changed. “I’m still doing research,” he said. “Now I just have the resources to pursue bigger, harder problems.”
Looking Ahead
Earlier this month, Perplexity announced the global launch of Comet, its new AI-powered web browser. Designed as a personal assistant, it can search the web, organize tabs, draft emails, and shop online — all through a conversational interface. By making the browser free to users worldwide, the company unlocks a new distribution channel and opens itself to a broader customer base.
“It feels great when you have an idea, you test it, and then the rest of the world agrees with you,” Yarats said.
