Ever wonder what it actually takes to train a frontier AI model?YC General Partner Ankit Gupta sits down with Nick Joseph, Anthropic's Head of Pre-training, to explore the engineering challenges behind training Claude—from managing thousands of GPUs and debugging cursed bugs to balancing compute between pre-training and RL. We cover scaling laws, d…

We are entering the era of Fintech 3.0. Regulatory clarity, growing consumer adoption, and low-cost chains have paved the way for a golden age of building in crypto — and at YC, Base, and Coinbase we want to fund builders to seize this moment. In this episode of Main Function, YC's Harj Taggar and Base's Jesse Pollak sat down to discuss what kinds …

For nearly two decades, Box co-founder and CEO Aaron Levie has been at the frontlines of how technology reshapes work—guiding the company through the rise of mobile, the cloud, and now the age of AI.In his fireside with YC General Partner David Lieb at AI Startup School, Aaron reflects on what it means to adapt a company over the long term, the har…

Amjad Masad is the co-founder & CEO of Replit, now valued at $3B after a recent $250M Series C. He's spent nearly a decade making programming accessible to all—and with the rise of AI, that vision is closer than ever.In this talk from AI Startup School on June 17, 2025, Amjad traces the arc of computing from mainframes to personal computers to a fu…

Bob McGrew helped build some of the most influential technologies of the past two decades. Bob was an early engineer at PayPal, an early executive at Palantir, and was recently Chief Research Officer at OpenAI - where he led the development of ChatGPT, GPT-4 and the o1 reasoning model. During his time at Palantir, he was a pioneer of the Forward De…

Michael Truell on June 17th, 2025 at AI Startup School in San Francisco.At 25, Michael Truell has already built Cursor into one of the fastest-growing companies in AI coding, hitting $100M ARR in just a year. In this fireside chat with YC General Partner Diana Hu, he shares the lessons that came from years of failed projects with his co-founders, w…

OpenAI recently released its first open-weights model since GPT-2, entering a field led by DeepSeek and Alibaba's Qwen.YC's Ankit Gupta breaks down everything you need to know about these top OSS models, including what sets them apart under the hood. He’ll compare their approaches to mixture-of-experts, long-context training, and post-training tech…

In this episode of Founder Firesides, YC General Partner Gustaf Alströmer is joined by Max Junestrand, co-founder and CEO of Legora, one of the fastest-growing legal AI startups in the world. In just 13 months, Max and his team scaled from 10 to 100 people, raised $80M, and cracked the challenge of selling to one of the most skeptical industries. M…

Navigating B2B sales for the first time can feel slow and overwhelming.Drawing from his experience founding Monzo and GoCardless, YC's Tom Blomfield shares his playbook for running a tight sales process that lands real, recurring revenue. He walks through each step—free and paid pilots, opt-out contracts, long-term deals—and shows how to prove valu…

Dylan Field on June 17th, 2025 at AI Startup School in San Francisco.Dylan Field co-founded Figma to bring the design process online and make it multiplayer. From a meme maker built on WebGL to a design platform powering millions, Figma’s journey hit a major milestone with its IPO last week.In this conversation, Dylan shares the early challenges of…

Brothers Chaz and Arnie Englander started Model ML after building and selling two YC companies. What began as a tool to help them analyze deals has grown into a full AI-powered workspace purpose-built for financial services, empowering firms to create automations and workflows that reflect exactly how their teams operate. And it's already being use…

Jared Kaplan on June 16th, 2025 at AI Startup School in San Francisco.Jared Kaplan started out as a theoretical physicist chasing questions about the universe. Then he helped uncover one of AI’s most surprising truths: that intelligence scales in a predictable, almost physical way.That insight became foundational to the modern era of large language…

For this episode of Design Review, YC’s Aaron Epstein is joined by Karri Saarinen, co-founder & CEO of Linear, one of the top designer-founders working today. Together, they'll review several sites from the YC community with an eye for how to build and maintain a high-quality brand. Thank you to these companies for volunteering to have their sites …

Chelsea Finn on June 17th, 2025 at AI Startup School in San Francisco.From MIT through her PhD at Berkeley, where she pioneered meta‑learning methods, and Google Brain, Chelsea Finn has built her career around teaching machines how to learn. Now an Assistant Professor at Stanford and co‑founder of Physical Intelligence, she’s using that foundation …

Amjad Masad started Replit to make programming accessible to anyone, anywhere. What began as a tool for learning to code has grown into a platform pushing the limits of AI-assisted software creation and recently surpassed $100M in ARR.On The Breakdown with Tom and Dave, Amjad shares the journey from his early days in Jordan, working on open-source …

John Jumper on June 16, 2025 at AI Startup School in San Francisco. John Jumper is a physicist-turned-computational biologist who led DeepMind’s AlphaFold team—and earned the 2024 Nobel Prize in Chemistry for solving protein folding, a decades-old scientific challenge. In this talk, he shares how a deep learning breakthrough at CASP14 turned into A…

Aravind Srinivas on June 16, 2025 at AI Startup School in San Francisco.Aravind Srinivas started Perplexity with one goal: to rethink how we search, browse, and interact with information online. In this conversation, he shares the journey from hacking together a natural-language-to-SQL search tool to building a product used by millions around the w…

Andrew Ng on June 16, 2025 at AI Startup School in San Francisco.Andrew Ng has helped shape some of the most influential movements in modern AI—from online education to deep learning to AI entrepreneurship. In this talk, he shares what he’s learning now: why execution speed matters more than ever, how agentic workflows are changing what startups ca…

François Chollet on June 16, 2025 at AI Startup School in San Francisco. François Chollet is a leading voice in AI. He's the creator of the Keras library, author of Deep Learning with Python, and the founder of the ARC Prize, a global competition aimed at measuring true general intelligence. He's spent years thinking deeply about what intelligence …

A fireside with Dr. Fei-Fei Li on June 16, 2025 at AI Startup School in San Francisco.Dr. Fei-Fei Li is often called the godmother of AI—and for good reason. Before the world had AI as we know it, she was helping build the foundation.In this fireside, she recounts the creation of ImageNet, a project that helped ignite the deep learning revolution b…

Kirsten Green, founder of Forerunner Ventures, has backed some of the most iconic consumer brands of the past two decades — from Warby Parker to Chime to Dollar Shave Club. In this conversation with Garry, she shares how great products (not marketing tricks) still win, why AI is unlocking a new kind of emotional relationship between consumers and t…

A fireside with Satya Nadella on June 17, 2025 at AI Startup School in San Francisco.Satya Nadella started at Microsoft in 1992 as an engineer. Three decades later, he’s now Chairman & CEO, navigating the company through one of the most profound technological shifts yet: the rise of AI.In this conversation, he shares how Microsoft is thinking about…

A fireside with Sam Altman at AI Startup School in San Francisco.Sam Altman grew up obsessed with technology, broke into the Stanford mainframe as a kid, and dropped out to start his first company before turning 20.In this conversation, he traces the path from early startup struggles to building OpenAI—sharing what he’s learned about ambition, the …

A fireside with Elon Musk at AI Startup School in San Francisco.Before rockets and robots, Elon Musk was drilling holes through his office floor to borrow internet. In this candid talk, he walks through the early days of Zip2, the Falcon 1 launches that nearly ended SpaceX, and the “miracle” of Tesla surviving 2008. He shares the thinking that guid…