Y Combinator

A camera that can see through walls

Applied Electrodynamics is building cameras that can see through walls and other opaque materials. Using radio waves, their system can see through drywall, marble, and other surfaces to locate studs,

What If We Stopped Using GPUs? | YC Paper Club

This week’s Paper Club is all about alternative compute. Modern AI has been shaped by a tight coupling between transformers, backpropagation, and GPUs. But as compute efficiency starts to plateau, the

Robotic factories that build robots

Tensr is building robotic factories that build robots. Their 12,000-square-foot factory is already making humanoids, end effectors, and even robots for the International Space Station. Every order bec

Robot-Use Agents: Why General-Purpose Models May Win in Robotics

One of the biggest surprises in AI over the last few years has been how well coding agents generalize beyond software. In a recent essay, MIT professor Philip Isola argued that we may be entering the

Rocket cargo delivery anywhere on Earth in minutes

Hop Aero is building rockets that can deliver cargo anywhere on Earth in minutes. They’re starting with military logistics and other time-sensitive payloads, including temperature-controlled materials

Autonomous construction on Earth and beyond

A lot of construction work is still done by hand simply because the machines to automate it don’t exist. That’s become a bottleneck for building things like solar farms, data centers, and other critic

Drone swarm defense

Attack drones are reshaping modern warfare, but many countries still lack an effective way to defend their airspace. Earendil Robotics is building autonomous interceptors, along with the software and

The State of Startups in 2026

YC works with thousands of founders every year, which gives us an early look at how startups are changing. Right now, the shift is striking: startups are moving from bits to atoms, nearly one in five

Why You're Getting Zero Replies To Your Cold Emails

The best outbound starts before you automate anything. Founders need to learn who actually has the problem, what gets their attention, and what makes them reply. YC Visiting Partner Christina Gilbert

Mass Magnetics: USA-made magnetics for robotics and defense

Magnets are becoming critical to the future of robotics, defense, and other major US industries. But 90% of rare earth magnet material is conventionally thrown away. The team at Mass Magnetics are rec

Happy Alumni Demo Day!

Introducing Early Access: An Invite only program for the Enterprise

Introducing the YC Early Access Network. 4x a year, senior technology leaders get early looks at YC's enterprise AI companies and help shape their roadmaps. Invite-only, by application. Fall '26 kicks

Why The Harness Matters More Than The Model | YC Paper Club

Harnesses get dismissed as just scaffolding, just prompt engineering, and not real research. But that couldn't be farther from the truth. The same model weights that score 30% on ARC-AGI score 95% wit

Paul Graham on what motivates founders

Paul Graham on what drives founders through the hard parts: “Being dutiful is not enough. The obstacles are too fearsome for mere dutifulness.” “You know what actually motivates founders day to day? T

Hard Tech Startups Are Built One Milestone at a Time

At Heart Aerospace, Anders Forslund built the company one material milestone at a time, using each one to earn the credibility and capital to build the next. “We really had no technology. I came to YC

Open Models Change The Economics of AI

Ollama (YC W21) is used by 9 million developers and 85% of the Fortune 500, giving co-founder and CEO Jeffrey Morgan a unique view into which AI models people are actually using and how that’s changin

Paul Graham On Startups, Ambition, and Great Founders

YC Visiting Partner Vivian Shen sits down with Paul Graham at the original YC office in Mountain View to talk about startups, AI, ambition, and what makes great founders. Apply to Y Combinator: https:

The World’s Largest Electric Aircraft Just Flew

Heart Aerospace (YC W19) just flew the largest electric airplane ever flown — a 100-foot wingspan, a takeoff weight of 25,000 pounds, and $5 of electricity to get it off the ground. In this episode of

Max Junestrand: You Need The Willingness To Learn Faster Than Anyone Else

Today, more than 3% of the world’s lawyers use Legora, and the company has grown from $1 million to $100 million in ARR since launching in October 2024. At Startup School 2026, Legora co-founder and C

Going In Deep On Data | YC Paper Club

This week's YC Paper Club is focused on data. Three domain experts give talks to break down the challenges and frontiers of training data, benchmarks, and multilingual pre-training. Apply to Y Combina