Varun Mohan: Why Insights Depreciate and Why Evals Compound

ℹ️ EPISODE INFO

Released

May 2, 2025

Duration

52m

Channel

Y Combinator

Watch on YouTube

▶ Open ↗

📝 EPISODE DESCRIPTION

Varun Mohan didn't set out to build one of the fastest-growing AI developer tools. He just knew his company had to change, or die. After initially betting on GPU virtualization, he saw the writing on the wall: if there was a future for his company, it would be at the AI application layer, not infra. Over a single weekend, he and his team pivoted to building Windsurf— a tool to help everyone, both technical and non-technical, write code faster and smarter. In this conversation, Varun shares the inside story of how they pivoted at the edge of failure, trained new models from scratch, outpaced giants like GitHub Copilot, and what the future of building with AI looks like. Apply to Y Combinator: https://ycombinator.com/apply Work at a startup: https://workatastartup.com Chapters (Powered by https://chapterme.co/) - 0:00 Intro 00:53 Windsurf - how big is it, where did it start? 3:00 The big pivot 6:20 Irrational optimism + uncompromising realism 7:52 Earliest versions shipped 10:26 The first customers 13:13 The transition from Codeium to Windsurf 19:45 Going up against Github Copilot 23:15 All insights depreciate; you need to keep proving yourself 26:50 Strong evals go a long way 30:15 Windsurf for hardcore engineering 31:55 Tips to get more precise changes when vibe coding 35:15 How will Windsurf evolve 38:00 Will AI become the infinite workhorse? 38:48 How does Windsurf interview candidates? 42:48 What happens if we get “just in time” software? 44:46 How many non-developers use Windsurf? 47:28 Thoughts on the GPT wrapper meme 49:17 Advice for new AI startups 51:39 Outro

🎤 SPEAKERS

• Varun Mohan

  guest

• Garry Tan

  host

🧾 EPISODE SUMMARY

In this episode of Y Combinator, featuring Varun Mohan and Garry Tan, Varun Mohan: Why Insights Depreciate and Why Evals Compound explores windsurf CEO on rapid pivots, AI agents, and democratized software building Varun Mohan, co‑founder and CEO of Windsurf, explains how his team pivoted from GPU virtualization (Exafunction) to AI coding tools in a single weekend after realizing transformer models would commoditize their original business.

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