Hard Tech Startups funded by Y Combinator (YC) in the San Francisco Bay Area 2026

We build brains for robots. We work with manufacturers like Unitree to make robots listen, speak, and act. You can program your robot out of the box by literally talking to it, no coding involved. Robots running Lightberry are emotionally intelligent, always on, and fully autonomous. Just like in Star Wars!

SigmanticAI is building an AI-native hardware development assistant that automates the entire RTL design flow, from natural language to synthesizable HDL and testbenches, inside a seamless VSCode fork. Powered by fine-tuned Verilog LLMs, reinforcement learning, and real compiler feedback, SigmanticAI iteratively refines code until it compiles and passes synthesis, no matter how complex the design. It’s like the Cursor for HDL design. In addition to code generation, SigmanticAI can generate token-level annotations and onboarding documents to accelerate ramp-up for new engineers. With support for both cloud and on-prem deployment, it integrates with existing EDA tools to dramatically reduce debug time, improve collaboration, and accelerate hardware design across teams

Check out the project: https://github.com/cactus-compute/cactus

What if every experiment you wanted to run could be modeled using AI? Godela is an AI-powered physics engine that gives engineers faster, cheaper replacement to simulations and physical prototypes. No set up, no wait. Just ask—and get simulation quality result.

Cascade Space is building a turn-key communications system for lunar and deep space missions. Our ground station network and integrated software tools work together to maximize uptime and availability, while reducing spacecraft iteration cycles from weeks to hours.

Atum Works is building 3D ASML. Founded by Caltech and NASA engineers, we're starting the next scaling law of semiconductor manufacturing, this time in 3D.

Maritime Fusion is building fusion reactors for ships and off grid energy markets. En route on this endeavor we’re commercializing High Temperature Superconducting (HTS) cable technology for power distribution while advancing the physics basis of our HTS tokamak to decarbonize global shipping. Breakeven fusion is coming soon, but the first-of-a-kind (FOAK) reactors will be costly, high maintenance, and have low capacity factors, leading to 5–10x higher electricity cost on the grid. Maritime Fusion is pursuing the most widely accepted approach to fusion, the tokamak, but specifically designed for the marine environment where the challenges that arise between breakeven and a commercially viable energy source are alleviated. The market we're targeting requires 15x less power, lower up-time, and costs the same as alternative fuels but without any emissions. Since fusion does not use highly radioactive fuels or materials – unlike fission – we sidestep the vast majority of regulatory challenges and safety risks associated with nuclear energy. Our team brings over a decade of industry and research experience in plasma physics, nuclear engineering, and electrical engineering with backgrounds at SpaceX, Tesla, Columbia University, and University of Pennsylvania.

Optifye.ai does AI performance monitoring for factory workers We place cameras in factories and use vision AI to tell supervisors who's working and who's not in real time. The shop floor has historically been a black box. With Optifye, manufacturing companies can now accurately measure worker output and boost efficiency!

Ultralight is a GPU-accelerated toolkit to embed modern HTML in games and native apps. Available for C and C++ on Windows, macOS, Linux, Xbox, PlayStation, ARM64 devices, and more. Developed in collaboration with leading game studios, built GPU-first on a new, lightweight fork of WebKit.

Finding new cures requires seeing what and where the abnormal molecules are in a diseased tissue, but current tools see less than 1% of those molecules. Biocartesian combines microscopy and new chemistries to see 50X more, offering unprecedented insights into disease biology and new therapies.

Sensei helps robotics companies scale and outsource their training data collection. Our hardware platform enables the collection of human-demonstration data at a tenth of the cost and twice the speed of current teleop approaches. Our software platform acts like Scale AI for robotics data: a large network of paid human operators use our low-cost collection platform to fulfill data-generation requests.

We’re building the next generation of warehouse robotics. In the US today, retailers spend approximately $10B per year paying human laborers to pick up and move cardboard boxes in warehouses. Existing solutions for automating this are expensive and difficult to install, which is why manual operation is still so prevalent. Our solution is different. We make swarms of small mobile robots that install into existing warehouses to provide a low-cost and robust automation solution for case picking and mixed-SKU palletization. Our novel technology allows these robots to be installed and operate at significantly lower cost than existing solutions while being both flexible and robust.

We build underwater data centers to cut power usage by up to 30%, operating GPUs cheaper and more sustainably. Our 1 MW capsule is being tested underwater in the SF Bay

Sorcerer is deploying a global network of persistent airborne sensors to fuel advanced weather forecasting. Our high-altitude balloons collect 1000x more data than existing systems and are already used daily by meteorologists to track extreme weather across the US and Central America.

1849 bio designs microbes enabling cheap metal extraction allowing miners to unlock value from low quality copper and gold ores. Surprisingly, the mining industry is one of the largest scale users of biotech in the world with biomining processes accounting for ~1% of global copper production. Biomining is ultra-low cost, running around ~$1/ton of ore vs ~$7/ton for conventional processes. Unfortunately, while biomining is cheap, it can’t be applied to over 80% of copper ores, leaving vast resources without profitable extraction methods. An estimated ~$800B of copper sit today in waste materials and stockpiles with negative unit economics. While a great deal of effort has been spent on optimizing microbial metal extraction processes, very little effort has been spent on optimizing the microbes themselves. To change that, we’re creating new biotech tools and platforms applied directly to the types of biology most relevant to miners. This enables us to develop new microbes and tackle some of the most difficult problems in biomining, unlocking billions in value from unprofitable resources while being more environmentally friendly than conventional processes. We’re world class microbial engineers. We met while doing our PhDs in synthetic biology, where we spent our time applying and developing the most advanced bioengineering technologies to engineer living cells. 

Conductor Quantum is building quantum superintelligence: AI that operates quantum computers to make scientific discoveries beyond human reach. Quantum computers let us understand the world at its most fundamental level, the path to new drugs, new materials, and discoveries no human can reach alone. A quantum computer is the perfect simulator of nature: it encodes the logic of reality into a programmable machine, atom by atom, electron by electron. Give AI that simulator and you open the door to discovery. The bottleneck is operating the hardware. Today, engineers spend days or weeks by hand to bring a chip to operating conditions for just two qubits. A qubit is the information-carrying unit of a quantum computer, the equivalent of a bit in a classical one, and a useful machine needs billions. Removing the human from that loop is only half the problem. Every command an AI sends to a quantum computer must be optimised for the specific hardware it runs on. We build the AI that operates quantum computers and tunes every machine it runs on. That is the path to quantum superintelligence.

Elodin creates flight software, simulations, and hardware for drones, satellites, and defense.

Zelos Cloud is the data platform for mission-critical systems that enables teams to observe, control, and test systems from prototype to production. The platform connects across entire ecosystems, capturing data from many protocols, enabling remote command execution, and facilitating team collaboration through shared workspaces and real-time annotations. By integrating data collection, processing, and visualization into one seamless pipeline, Zelos Cloud eliminates complexity and breaks down silos between engineering, operations, and quality teams.

We're building autonomous robots to make surgery safe, easier and more efficient. Robots currently perform about 1/4 of surgeries but only help with the physical aspects. We use AI to make surgery cognitively easier. This has far greater potential to improve outcomes and reduce costs. Founded by 3x founders from medtech and autonomous vehicles, we're on track to be the fastest surgical robot to market of all time. First indication is prostate enucleation.

Auricle is a medical device company building a breakthrough neurostimulation implant to restore hearing in millions of patients who no longer benefit from hearing aids, get less than 60% on a word recognition test, but aren't prepared to make the jump to a cochlear implant. Our approach preserves remaining natural hearing through a reversible and less invasive surgery, addressing the key concerns that hold most patients back from getting a cochlear implant (currently the only treatment option for these patients). The company spun out of Stanford Biodesign having completed two acute human clinical studies demonstrating the approach will work. The team is now focused on developing their full implant system for their first clinical trial. Auricle addresses a currently unserved profile of hearing loss that affects a growing population of 3.5 million patients in the US and represents an immediately accessible $1.2B market opportunity with existing reimbursement.

The DROP by Rex.Fit is an AI wearable camera that automates nutrition tracking using computer vision. It has garnered more than 93k USD in preorders (~450 units) since its launch last month. The nutrition estimation and recommendation tech behind the DROP is already integrated as an API for fitness chains, generating hundreds of thousands of dollars in yearly revenue for them. The DROP is built by brothers, sports nutritionists and computer vision engineers from the Swiss Federal Institute of Technology (ETH Zurich).

Polymath is building a general autonomy stack for cautious vehicles. Our software allows any industrial vehicle - whether it's a tractor in a field or a bulldozer in a mine, drive itself. We bundle together AI, ML, Controls, ROS, Safety and best-in-class deployment practices to enable our customers to tell automated vehicles to do via a REST API. We're on more robots than we have engineers, are seeing our revenue (and robotic fleet) grow rapidly, and are looking for folks who want to help automate the world.

Integrated Reasoning builds efficient computer processors that are tailored to the memory access patterns of Karp's 21 NP-complete problems. We’re making it 100x - 10,000x faster to perform computations like scheduling airline pilots or optimizing packing layouts for shipping containers.

We bring Tesla autonomous manufacturing to every automaker and other producers. At Tesla, we were the core autonomous factory team and we’re now building the smart cameras and robotic guidance tools that provided the main advantages at Tesla

AirMyne is building machines to capture & remove carbon dioxide from ambient atmospheric air so it can be utilized or sequestered downstream. Our team is based in Berkeley, CA.

Observant AI is an iPhone-based driver monitoring system for commercial fleets. It uses machine learning + iPhone's depth sensors to detect unsafe driver behavior, prevent accidents, and save lives.

We use the printing methods used for newspapers, packaging, posters, and other graphic media to make beautiful, emissive electronic displays with high-end OLED technology aimed at low-cost applications. Our displays are paper-thin, flexible, and can be easily custom printed in a variety of shapes and sizes, allowing hardware designers to use displays and indicators on curved surfaces and in new ways.

We build automated robots for concrete floor construction. One person with our robots does the work of 6 construction workers.

Teleo converts heavy equipment, like dozers, trucks, and loaders, into supervised autonomous robots. This enables a single operator to remotely operate multiple machines while sitting at a remote control center, unlocking productivity gains for the General Contractor.

We're building a mobile and wearable digital wallet that makes interacting with payments, identity, and authentication seamless, fun, and empowering. Acquired by OURA in 2023