Y Combinator

E Bufar, head of design at Y Combinator, demonstrates how she uses AI tools like Claude and Aqua to design products end-to-end, eliminating traditional design workflows. She walks through three projects—Paxel, Sodazine, and Startup School—showcasing techniques like voice-to-code development, comprehensive markdown documentation, and rapid iteration through disposable design tools.

The speaker explains dot plots, a visualization tool that displays individual user behavior over time by plotting user actions on a 2D grid. Unlike aggregate metrics like DAU/MAU, dot plots reveal usage patterns, feature adoption, and retention issues that are invisible in traditional dashboards.

Eddie Kim, Gusto co-founder and head of technology, discusses Gusto Co-founder, an AI product that automates business processes for small business owners. Built in 10 weeks by a 5-person team during a missed flight layover, the product lets customers automate tasks like payroll and scheduling through SMS and Slack, while proactively suggesting optimizations and uncovering hidden opportunities like tax credits.

Y Combinator leaders and Indian venture investors discuss why India is positioned to create the world's largest AI companies, emphasizing that success now depends on technological edge rather than market knowledge, and that AI has democratized startup building for young founders with high agency and customer obsession.

Max from Y Combinator provides tactical guidance on acquiring a startup's first 10 customers, emphasizing that success comes from understanding where target customers spend time, leveraging warm networks, showing up in person, and doing unscalable manual work rather than relying on automation tools.

Bryant Chou, co-founder of Webflow and now founder of Ploy, demonstrates his new AI-powered website and marketing platform that builds and optimizes websites while running marketing on autopilot. The conversation explores how domain expertise amplifies AI capabilities, and why experienced founders have a unique edge in the current AI era. Ploy is positioned as a full marketing brain for small businesses and startups, going beyond website creation to SEO, GEO, analytics, and customer intelligence.

YC partner John argues that founders should stop overthinking startup ideas and instead commit fully to a single idea, going deep on customer understanding. He presents a rubric for validating ideas through immersive customer research and outlines three qualities of strong AI-era startup ideas. He emphasizes that even failed deep dives produce valuable data and often surface better underlying opportunities.

Lalit Keshre, co-founder of Groww, discusses the company's journey from a failed robo-advisor to India's largest investment platform, emphasizing customer obsession, radical transparency, and organic growth. He shares how Groww achieved product-market fit within 10-15 days of launching their revamped product in May 2017 by showing all investment products with full transparency. The conversation covers co-founder alignment, navigating regulation, and how AI is lowering barriers to building consumer products.

A research meetup covering five AI topics: protein language model scaling laws (ESM Cambrian), self-play for LLMs (SGS algorithm), streaming RAG for voice agents, formal verification with Lean, and agentic software engineering workflows. Presenters demonstrate how foundational AI scaling principles are transferring into biology, mathematics, and production engineering.

Vidit Aatrey, co-founder of Meesho, discusses the company's evolution from a local fashion marketplace to India's largest shopping app with 250 million annual buyers. He explains how customer obsession drove multiple pivots, including abandoning their successful WhatsApp-based social commerce model to launch a direct consumer app in 2021. He also shares how AI is now the next frontier for reaching the remaining 750 million potential Indian consumers.

Pedro Franceschi, co-founder and CEO of Brex, discusses how his company has gone deep on AI adoption, from personal use of Claude to enterprise-wide deployment of AI agents. He argues that CEOs must personally lead AI transformation, treating it as a company-wide refounding rather than a departmental initiative. The conversation covers AI agent security, token spend management, customer world models, and the broader philosophical shift required to build companies in an AI-native way.

Former attendees of YC Startup School share testimonials about how the event inspired them to found startups and apply to Y Combinator. The event is praised for its high-caliber speakers, community of ambitious peers, and its role as a gateway into the startup ecosystem. Attendees strongly encourage others to attend, calling it one of the most impactful experiences of their lives.

Mukun, co-founder of Emergent, discusses how his AI-native no-code platform reached $100M ARR and 8.5 million users in just 9 months after launch. He shares his journey from Google to Dunzo to Emergent, explaining how six months of post-burnout tinkering with AI models led to the founding insight. He also offers advice on thinking globally from day one and betting on exponential AI progress.

Paxel is a newly launched tool that analyzes Claude and Cursor coding sessions locally to generate a personalized 'builder profile' across five dimensions. It runs in Docker, keeps code private, and is free to use. Y Combinator is also integrating Paxel tokens into their Startup School application process.

Max Junestrand, CEO of Legora, discusses how he recruited Jude Law for a marketing campaign, his journey through Y Combinator, and Legora's growth from a small startup to nearly $100M+ ARR with ~500 employees. He also addresses competitive strategy against large AI platforms and the shift toward agentic AI workflows in legal tech.

Charlie Holtz, co-founder of Conductor, demonstrates his AI-agent orchestration workflow where he manages multiple Claude and Codex agents simultaneously on his Mac to build software without writing code himself. He discusses opinionated design decisions, 'slot-free zones' to prevent AI code quality degradation, and his philosophy that code is becoming 'sawdust' — a byproduct of well-crafted prompts. The interview covers token spending, tech stack, and his vision of humans as conductors of AI orchestras.

This transcript outlines a playbook for building AI-native services companies, where AI does the bulk of work to deliver outcomes in large markets like tax, law, and insurance. The speaker covers market selection, team formation, product building, sales strategy, and P&L structure. The core thesis is that these businesses can achieve software-like margins (50%+) on markets two to three times larger than traditional software.

Varun, co-founder of GigaML, shares his journey from IIT student to building an AI customer support company, having turned down a $550K quant firm job offer. The company pivoted multiple times before finding product-market fit in AI customer service agents, winning major clients like DoorDash and top crypto exchanges. Varun reflects on lessons around selling before building, the outsized leverage of coding agents, and the value of 'burning the boats' to force real commitment.

The inaugural YC Paper Club at Pioneer featured five presentations on cutting-edge AI research topics including speculative decoding for faster LLM inference, diffusion model predictive control for robotics, world models, generalization theory, and data-efficient pre-training. The event brought together researchers and founders in the Bay Area to build a community bridging academic research and startup development. Each presenter shared novel algorithms and findings aimed at advancing AI capabilities, efficiency, and theoretical understanding.

YC General Partner Pete Kumman describes how Y Combinator built internal AI agent infrastructure over the past year, including a shared tool registry with 350+ tools, a centralized database for agent context, and self-improving skill loops. The conversation covers the principles behind building 'superintelligence' inside organizations through shared context, transparency, and agentic workflows that compound organizational knowledge over time.