Jake Heller is the co-founder & CEO of Casetext, the AI legal startup behind CoCounsel, which was acquired by Thomson Reuters for $650 million.In his talk at AI Startup School on June 17th, 2025, he shared how his team did it—from picking the right idea to building AI products that actually work—and how founders can turn a cool demo into a reliable tool used by real customers.…

Nearly every modern AI model, from ChatGPT and Claude to Gemini and Grok, is built on the same foundation: the Transformer.In this video, YC's Ankit Gupta traces how AI learned to understand language — from early RNNs and LSTMs to attention mechanisms and the breakthrough 2017 paper Attention Is All You Need — the discovery that unlocked the modern AI era.…

Every founder faces moments where they’re not sure what to do next — such as how to go to market with AI products, when to pivot, and who/when to hire. In this episode of Office Hours, YC partners Pete Koomen, Brad Flora, Nicolas Dessaigne, and Gustaf Alströmer answer real questions from founders and share stories about how great teams build conviction, learn faster, and make better decisions as they grow.…

For years, we've heard two major narratives about AI. One predicting the end of human work, the other dismissing it as hype. The truth is more nuanced, and more hopeful.From radiology to software engineering, the pattern repeats: as technology makes tasks cheaper and faster, demand for human creativity and judgment grows.YC's Garry Tan explores what history, economics, and real companies show us— that technology doesn't replace people, it redefines what we can do.…

Karri Saarinen is the co-founder and CEO of Linear, the issue tracking tool used by thousands of high-growth companies. Before Linear, he was the first designer at Coinbase and later a lead designer at Airbnb.On Design Review with YC's Aaron Epstein, Karri shares how his design background shaped Linear’s product philosophy, why quality and craft matter from day one, what founders should look for when hiring, and how AI is changing the way teams build. It’s a deep dive into building products that truly stand out.…

Paul Gross and his team at Remora are trying to do something that’s never been done before. They're building mobile carbon capture devices for commercial trucks and trains—capturing CO2 from moving vehicles before it enters the atmosphere, then turning those emissions into revenue by selling it to customers that can turn the liquified CO2 into new products. In this episode of Hard Tech, YC's Gustaf Alströmer visits Remora's headquarters outside Detroit to see how a recent college grad with no engineering background is helping transform the $2 trillion transportation industry.…

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, data strategies, team composition, and why the hardest problems in AI are often infrastructure problems, not ML problems.…

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 of companies they're most excited to see, why this is such an exciting time in crypto, and what the future could look like onchain.More on our latest RFS: https://www.ycombinator.com/blog/build-onchain…

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 hard lessons of staying relevant across multiple technology waves, and why he believes AI represents the most transformative shift yet.…

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 future where AI agents can create software on demand. He predicts that the value of traditional software will approach zero, fundamentally reshaping how companies are built and how work gets done.…

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 Deployed Engineer (FDE) model, a strategy that is at the heart of the AI boom today. On this episode of The Lightcone, he explains how FDEs became central to today's startups, why "doing things that don't scale at scale" works, and where he sees the biggest opportunities for founders working in AI.…

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, why he believes programming is still essential even as AI changes how we code, and how Cursor is taking on GitHub Copilot with the conviction that all of software development will flow through models.…

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 techniques that shape reasoning and alignment—and explore how different design choices lead to surprisingly similar performance.…

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. Max shares insights on building a successful vertical AI company, selling to conservative markets, and sheds light on what the future of legal tech looks like.…