Y Combinator

Bill Abster from Applied Electromagnetics discusses his company's breakthrough technology that uses radio waves and high-frequency antennas to create 3D images of objects behind opaque materials. The system processes echoes in real-time using GPUs to generate detailed depth maps, and the company has achieved significant progress in just 4 months by maintaining rapid iteration cycles.

A YC Paper Club discussion exploring alternatives to GPU-based computing, featuring presentations on optical computing, neuromorphic chips, and biological computing approaches. Speakers argue that GPU efficiency (FLOPS per joule) has plateaued, necessitating fundamentally different computational substrates inspired by the brain's 20-watt energy efficiency.

Tensor is building a 12,000 sq ft robotic factory that manufactures robots, including humanoids and specialized grippers. The company, founded by Berkeley researchers with autonomous vehicle and manufacturing backgrounds, treats the entire factory as a learning system that improves manufacturing processes with each customer order.

This discussion explores how large language models like Claude (Astra) are enabling robot control through code generation and tool use, building on foundational work like RT2 and visual language-action models. The speakers from Waddle Labs and RoboCurve explain how models trained on diverse data modalities—including web text, computer usage, and coding—are converging toward general-purpose robot agents that can perform complex physical tasks within the next 2 years.

Matthew, CEO of Hover Arrow, discusses the company's mission to deliver cargo anywhere on Earth within minutes using rocket technology. The startup has secured $1.37 billion in commercial letters of intent, with primary focus on military applications and emerging interest from industries requiring rapid, temperature-controlled delivery of perishable goods.

James, co-founder of Fossma Robotics, discusses building autonomous construction equipment for large-scale infrastructure on Earth with the long-term goal of enabling construction on Mars and the moon. The company has already deployed systems that installed 11,000 solar panels and recently signed a major contract with the top construction company in the US.

YC is experiencing a major shift toward hardware and physical technology companies, with hard tech representation growing from 8% to 20% of their portfolio. This trend is driven by AI acceleration enabling faster development, macro factors like SpaceX's success and geopolitical concerns, and the emergence of agentic AI that can automate entire job workflows rather than just point solutions.

A comprehensive guide to improving outbound sales by a YC visiting partner, covering eight key strategies: starting with manual outreach before automation, prioritizing prospect targeting over perfect messaging, crafting compelling value-focused messages, optimizing LinkedIn profiles, analyzing reply rates diagnostically, consistent follow-up, time management, and leveraging customer feedback for messaging improvements.

Mass Magnetics recycles rare earth magnets from electric vehicle motors to produce domestically-made magnets for robotics and defense applications. The company uses a capital-efficient recycling approach that bypasses expensive mining and refining processes, extracting and processing magnets that would otherwise be discarded.

Susan Kare discusses her pioneering work designing icons and fonts for the original Apple Macintosh, sharing design principles focused on simplicity and metaphor, along with advice from influential figures like Paul Rand that shaped her career in digital design.

Chelsea Finn discusses advancements in physical intelligence, highlighting the development of general-purpose robots capable of performing various tasks autonomously. Key techniques include reinforcement learning, efficient data utilization, and the importance of memory in complex task execution.

Ali Haghani discusses CircleBack, an AI note-taking tool designed to capture, organize, and automate meeting content. He shares insights on his hardware setup, unexpected uses of CircleBack, and the evolving landscape of software engineering as AI capabilities grow.

YC Paper Club discusses why robotics remains unsolved despite repeated predictions of breakthrough years, presenting four fundamental challenges (physical modeling, deformable objects, sensorimotor feedback, embodiment drift) and showcasing recent advances in memory-augmented policies, embodied reasoning, sim-to-real learning, and world action models.

Max Hodak, CEO of Science (a retinal prosthesis company), explains that deep tech startup success is determined by infrastructure and iteration speed rather than technical brilliance. He emphasizes that proper systems for purchasing, recruiting, and performance management are as critical as the core technology, and shares specific processes Science uses to scale efficiently.

Philip Johnston, CEO of StarCloud, discusses building data centers in space to address Earth's energy bottleneck for AI. The company launched its first satellite (StarCloud 1) in November 2025 with an Nvidia H100 GPU, and has raised $170 million to deploy a constellation of 88,000 satellites that could provide 20 gigawatts of compute capacity.

Patrick Collison discusses Stripe's founding story, the importance of concrete customer problems, and shares data suggesting it's the best time ever to start a business. He argues that despite AI advancement, there will be many winners rather than centralization, and emphasizes the value of deep learning alongside AI tools.

This YC Paper Club event focused on chip and kernel specialization in AI systems, featuring discussions on multi-GPU kernel optimization, energy-efficient inference, AI-generated kernel code, heterogeneous inference hardware, and GPU-accelerated game engine simulation. Speakers explored how specialization across hardware, software, and algorithms can dramatically improve efficiency and performance across different AI workloads.

Blake Scholl, founder of Boom Aerospace, discusses building the first independently developed supersonic jet by applying software development principles to hardware manufacturing. He argues that startups can compete in regulated industries by building solutions that solve regulatory concerns, and emphasizes that passion, iteration, and vertical integration are key to breakthrough innovation in deep tech.

Boris Cherny, creator of Claude Code, discusses how Anthropic's Opus 5 model represents a major leap in AI capabilities, requiring a fundamental rethinking of how to build AI products. Rather than accumulating complexity, successful builders must regularly delete system prompts and code to "unhobble" the model, allowing it to tackle increasingly complex tasks like rewriting entire codebases and maintaining software automatically.

The speaker argues that API communication is fundamentally broken across the industry, with breaking changes and new features going unnoticed. Since agentic coding tools have proven viable and developers accept external tool access to codebases, API providers should automatically apply changes to customer code rather than just announcing them—similar to how Dependabot works for dependencies.