Y Combinator Startups in Seattle 2026

Kyten Technologies is building a factory to manufacture custom aerospace-grade battery packs. 100,000+ drones, submarines, and satellites are being built in the US, but the legacy supply chain can't keep up. During our six years at Starlink, we put 5,000+ battery packs into space. Now, we're bringing rapid development and volume production of aerospace-grade battery packs to the entire industry.

Chamber puts your AI infrastructure on autopilot, and saves your machine learning engineers hours of manual effort. Our agents continually monitor, detects failures, provide root-cause analysis, resolve issues, and optimize AI workloads and scale across clouds. It operates like an autonomous infrastructure team, helping save your research and engineers hours each day, and debugging workload performance issues. Your ML teams move faster, infra waste drops, and GPU bottlenecks disappear.

Constellation Space is building the autonomous infrastructure layer for the next generation of space networking. As satellite constellations rapidly scale from hundreds of nodes to tens of thousands, traditional ground-based orchestration fundamentally breaks down. ConstellationOS bridges this gap by providing zero-intervention network handoffs, predictive thermal load-balancing, and sub-second optical routing. Our founding team spent years building and operating satellite systems at SpaceX, Blue Origin, and NASA. We started Constellation to solve the problem we kept running into: reactive monitoring doesn't scale. We are building the sub-second routing protocols and hyperscale load-balancing infrastructure that will manage the future of off-world telecommunications and compute. hello@constellation-io.com

We are building an autonomous robot to precisely eliminate weeds and leave crops untouched. Despite $100 billion being spent annually on weed control, weeds still cost the US economy $46B/year. Weeds steal sunlight and nutrients from crops, forcing farmers to choose between higher costs and lower yields. Moreover, many farms still rely on hand labor to control weed growth. The process is slow, expensive, and increasingly difficult due to constant labor shortages (1 out of every 5 US farm positions go unfilled each year). Our robot nicknamed the Field Hand is able to automate one of the worst jobs on a farm and will help healthily feed the world.

Silurian is building foundation models for simulating Earth, starting with weather. From assessing the risk of wildfires to predicting the energy grid load, we provide an infrastructure layer for our planet. Our frontier models push the boundaries of what can be simulated on Earth and improve decision making across vital sectors including energy, insurance, agriculture, and logistics.

bluedoor is a CLI tool for stock research.

Clearly AI automates security and privacy reviews with AI. We performed hundreds of reviews at Amazon and Moveworks and now we're building the product we wish we had. Our users complete reviews in minutes instead of days. Emily and Joe are technical co-founders and senior engineers. We met in 2019 while working on an Alexa security review.

Starcloud is building data centers in space, initially to provide GPU compute to other satellites, and later to address the rapidly growing demand for energy caused by the deployment of AI. Falling launch costs give Starcloud access to abundant energy, radiative cooling, and the ability to rapidly scale in space. In November 2025, just 21 months after founding, Starcloud launched its first satellite, Starcloud-1 to space. This has an Nvidia H100, which is 100x more powerful GPU than has ever been operated in space before. With this, they became the first entity to train an LLM in space and the first to run a version of Gemini in space. Starcloud will soon also run high-powered inference on Capella SAR data on orbit for the first time. Starcloud is launching its second satellite in October 2026, which will have 100x the power generation of the first and generate more cash than it costs to build and launch. Starcloud expects that within 10 years, most new data centers will be being built in space for the energy. In March 2026, Starcloud raised a $170M Series A led by Benchmark, becoming the fastest unicorn in YC history, just 17 months after demo day.

We build generative AI tools that enhance the fan engagement experience. Want to remix Taylor Swift in the style of Slayer? Now you can with our new product Groove.

Manifold is revolutionizing the spot freight procurement process for Carriers, Brokers, and Shippers. Our inaugural product transforms the booking process for spot shipments, significantly reducing empty miles and increasing revenue. We do this by aggregating spot shipment opportunities from a variety of shipper and brokerage sources into a single location. Andrew and Oliver bring deep domain expertise of freight from their pivotal roles at Convoy, where they were engineering leaders automating processes that were scaled to handle over 10,000 weekly shipments. This background has been instrumental in shaping Manifold's innovative approach. In just two months since launching Manifold has achieved $5,100 in monthly revenue, showcasing the pressing demand for our product. Manifold is poised to transform this $100+ billion industry. Not only will we streamline spot freight procurement operations but we will also redefine the industry's cost structure for the better.

Terrakotta is a power-dialer that lets sales reps leave AI-generated voicemails. Our first customers are Commercial Real Estate brokerages that use Terrakotta to clone their brokers voices, dial prospects and when no one answers, leave an A/B tested, personalized voicemail that gets a callback.

Only 2 out of 10 ML models make it from experiment to production. Preloop helps automate the process of deployment, helping companies realize more value from their machine learning teams, while focusing teams' attention on science instead of engineering.

VetRec automates the process of taking clinical notes for veterinarians in a matter of seconds. Veterinarians should just review clinical notes, not spend time creating them. A visit with a pet is precious and 100% of the focus should be spent on the pet, not on notes. VetRec is the veterinarian's best friend.

Talc helps hospitals pull events and data out of messy EHRs.

Hubble is building a global satellite network that any Bluetooth-enabled device can connect to, even without cellular reception. Our mission in life is to get a billion devices connected to the network and unlock a new era of human-machine collaboration.

Boundary is building BAML -- a programming language to build AI agents. We used to code in assembly, and moved on to C. From C, we moved on to higher level languages like Python. Now we are going from Python to natural language. What does the code look like when 50% of the business decisions is decided by an AI agent / prompts? How do you test these AI components? We made BAML to address these problems. BAML helps has built-in tools to test, observe, and work with structured LLM outputs / tool calling natively in the language 10x faster. With BAML you can also instantly parallelize LLM Calls, or react to certain events or changes in your pipelines, without having to write any boilerplate. It's like using 'React' for AI. BAML code can used from any other language -- providing a standardized way to organize and declare any LLM or AI code.

Decohere is building product and infrastructure for real-time generative AI. We enable our customers to iterate towards their creative vision without waiting for long-running GPU jobs.

Matano is a modern SIEM, built for cloud-first security teams. It replaces traditional SIEM databases like Splunk or Elastic with a cybersecurity platform built on top of a cost-effective Security Data Lake.

Radical’s StratoSats are autonomous platforms that provide satellite-like services on demand. They fly within Earth’s atmosphere to provide persistent, high performance infrastructure across applications in earth observation, connectivity, and more. Unlike satellites, StratoSats navigate freely without the need for rocket launches or orbits - reducing costs, increasing flexibility, and ensuring customers get the targeted coverage they need.

Aurelian builds AI tools that help 911 centers handle more with less, so telecommunicators can stay focused on what matters most and communities get the response they need. AVA is a conversational AI agent that answers non-emergency calls; the agent routes, triages, and resolves the calls without any human intervention. By handling administrative calls like noise complaints, lost dogs, and parking inquiries, AVA eliminates hold times and lets call-takers focus their energy on actual emergencies. CORA supports call-takers on the calls that matter most. CORA is an on-screen assistant that delivers real-time SOP checklists, smart reminders, and contextual guidance as an emergency call unfolds, so dispatchers stay calm, consistent, and confident when every second counts. When AVA detects an emergency mid-call, it transfers the caller to a telecommunicator and passes along the caller details, location, incident type, and key statements directly into CORA. The call-taker never starts from scratch. The problem we're solving is serious. The average emergency communications center is 30% understaffed nationwide. Staffing shortages drive burnout and attrition, which makes the shortage worse. Meanwhile, 60-80% of the calls coming in aren't even emergencies at all. Aurelian addresses both sides of that equation: AVA reduces unnecessary call volume, and CORA makes every emergency call more manageable for the people handling it. Aurelian is live in centers across the country, answering thousands of non-emergency calls every day, and is backed by New Enterprise Associates and Y Combinator. Aurelian is growing rapidly; we are hiring people who want to help scale this work and make a real difference in public safety infrastructure for communities across the country.

Intuned is a code-first browser automation platform with an AI agent that builds and maintains your automations. Developers use Intuned to deploy scrapers, RPAs, and crawlers as production-ready TypeScript or Python projects — with stealth, CAPTCHA solving, proxies, auth, and scheduling handled out of the box. The agent builds projects from a prompt, fixes failed runs, and can self-heal automations autonomously when websites change.

Designers and product managers are often locked out of prototyping on top of their existing product. Security policies, large code base, and complex build setup all stand between the promise of code-first front-end design and reality. The Chordio Workbench helps non-technical team members prototype new experiences on top of their existing products even when they don’t have access to the source code. The full workflow runs in Claude Code on your local machine. It starts with cloning the front-end of the product into the workbench repository directly from the browser and compiling it into code a coding agent can work with. This means anyone can start prototyping in minutes without having to worry about a complex environment setup. The Workbench includes agent skills to help ensure prototypes meet team standards, are backed by research, and presented to stakeholders with clarity.

The platform powering human like phone calls at AI speed

Instant Labs started in 2005 by building the fastest domain search engine on the internet: https://instantdomainsearch.com. People have performed over 2.5M searches and purchased 250K domains with our free tool.

AgentRouter lets agents discover, pay, and execute APIs.

Uberduck makes tools high-quality audiovisual content creation tools for product companies, brands, agencies, and musicians. We offer audio generation, image generation, and video generation functionality, including enterprise workflow APIs to power end-to-end video creation experiences. Vocal samples and full songs produced by our text-to-speech, text-to-singing, text-to-rapping, lyric video generation, and voice conversion technologies power: - AI remixes and original songs for musicians ranging from hobbyists to the largest DJs in the world. - Personalized musical content in marketing campaigns. - A variety of music-related consumer experiences built on top of our APIs.

Cash Flow Portal is an investment management platform for real estate. We launched 5 months ago, and we have 6-figure ARR, growing 50% month over month, with 300 syndicators and 3,000 investors. We’ve grown quickly because I am a syndicator myself. Having raised $20MM for my own deals, I know how painful it is to manually prepare Docusigns, send wire instructions and wrangle investors. I also happen to be friends with 2,000 other syndicators just like me needing a solution for managing their investors. I’m not just a syndicator. I spent most of my career as an engineering leader at Lyft, Twitter, and Amazon. $20K ARR per syndicator gives us a $2B TAM. Having achieved my own financial freedom through real estate investing, our mission is to serve all real estate investors and help them achieve financial freedom.

Strac is an agentless Data Discovery (aka DSPM - Data Security Posture Management), Data Classification & DLP (Data Leak Prevention) that automatically discovers, classifies and remediates sensitive data (alert, label, redact, mask, block, delete). Strac protects SaaS, Cloud, Gen AI, Browsers, On-Prem and Endpoints like O365, Slack, GDrive, AWS, Salesforce, ChatGPT, Jira, Mac, Zendesk, Azure, On-Prem (On-Prem, MS SQL SAP) and 40+ integrations. Strac protects enterprise companies like UiPath, Databricks, thredUP, B Capital, Crypto (dot) com!

Equipt Health makes it easy for any healthcare company to offer prescription medical devices to patients. We handle the whole process: the packaging, the logistics, the clinical (via our provider network) and technical support, and the return of data from connected devices. We're starting with the diagnosis and treatment of sleep apnea at heliosleep.com.

We have built a platform that enables drug discovery and development for previously undruggable genome regulators ("the regulome"). We accomplish this by moving drug discovery out of artificial systems where regulome proteins fail to function properly, and back into live human cells. Our technology combines innovations in automated cell processing, next-gen proteomics, and advanced data analytics to measure a drug's effect on the entire regulome in one experiment.

Nova: Radically improving access to and from orbit. We’re unlocking the space economy by harnessing the power of full and rapid reusability with Nova, our 100% reusable rocket. Nova offers affordable access to, through, and from space with a 20x reduced cost to orbit. Our reusable upper-stage vehicle delivers on-demand access to any orbit at any time. Its unmatched capabilities enable dynamic space operations, including capture, reposition, long-dwell operations, and return of assets, as well as space cargo and logistics missions.

aSim lets you build and share apps with friends. Prompt > Run > Remix > Repeat, and you'll have the next TikTok in no time.

Awtomic powers DTC brands with an easy-to-use subscription management and discovery platform. Starting with a Shopify app, we'll give merchants the subscription product power of premium subscription brands like Dollar Shave Club and Ipsy. As we grow our support for more eCommerce platforms and merchants, we'll help customers discover new brands through cross-sells and make it easier for them to manage their subscriptions in one place.

We founded Inspectify with the goal to make a platform that helps inspectors, real estate professionals and home buyers alike. We see a tremendous opportunity to apply the latest technology to make inspectors more proficient and effective and make home inspections more engaging and value add to home buyers. We are just getting started, but are excited to provide much needed disruption in the space!

Our mission is to empower the world’s hiring teams to grow engaged, high-performing organizations - by delivering human connection at scale through innovative technology, commitment, and fairness. High-volume hiring is extremely broken - it is inefficient, ineffective, and biased. Our mission is to fix what is broken. We believe great hiring processes are centered around quality conversations between candidates and employers and a future where every candidate’s journey starts with a conversation - a future where candidates are considered without bias or archaic artifacts like resumes and cover letters.

Construction costs are climbing out of control, there is a declining construction workforce that gets smaller with every recession. Meanwhile, we’ve got a housing crisis in our major cities. Green Canopy NODE is the combination of NODE - construction technology start up that develops a house assembly kits that we manufacture in our factory in Seattle, and then ship flat-pack - like Ikea, and Green Canopy a vertically integrated developer, general contractor and real estate fund manager already operating in Seattle and Portland. We are continuing to develop and launch construction technology solutions including prefab components and software into our pipeline of residential projects ranging from small apartments, town houses, single family homes and small dwellings. Our mission is to build homes, relationships, and businesses that help regenerate communities and environments.

Latchel is the only end-to-end platform that automates maintenance coordination and delivers best in class resident amenities. We service over 80,000 homes across over 400 customers in all 50 states of the US. We’re growing rapidly and need a Product Designer to continue our rapid growth trajectory.

Gordian is pioneering seamless, personalized travel powered by world-class software. We don’t remodel legacy platforms — we invent what's next. Built on the values of freedom, impact, and ownership, we emphasize in-person collaboration, deep thinking, and bold execution. We believe in a high-talent, low-ego team with the energy to build something extraordinary.

Rebellyous Foods is a food manufacturing technology and production company defined solely to catapult meat alternative production toward price parity with animal-based meat. Rebellyous implements novel food manufacturing equipment and processes in large-scale production to produce low-cost plant-based meat at high volumes. These goals are achieved through uniquely designed food products, the use of high-throughput manufacturing automation and ‘smart’ production centers, and the development and utilization of new innovative low-energy manufacturing tools. Working closely with industry partners, Rebellyous makes plant-based meat sustainable, affordable, and widely available.

Worklytics identifies leading drivers of employee engagement, without the need for repetitive surveys. It does this by passively analyzing anonymous collaboration data, in tools like Google Workspace and Slack, and detecting patterns that lead to greater employee satisfaction. Worklytics uses these insights to promote positive organizational change by proactively nudging leaders and managers.

Sigma Genetics develops devices that can deliver DNA, RNA, and other charged molecules into cells by using magnetic fields. When compared to conventional electroporation, this technique has several key advantages, which include: the absence of arcing, the ability to scale, and the benefit of being non-invasive for in vivo applications. This platform technology can be applied to a wide range of applications- cell therapies, cancer drug delivery, DNA vaccines, biopharma manufacturing, and cosmetics.

BloomAPI simplifies how medical records are transferred. Today the majority of records are still moved by fax and couriers. Patients, Doctors, and Insurance companies all benefit when medical records are available when they are needed for the care of patients. We make this possible.

Deako believes that everyone should be able to enjoy the wonderful experiences of smart lighting, regardless of their budget. We invented the modular light switch, giving homeowners maximum flexibility to customize and upgrade their systems, at any time, in minutes and without turning off the power. Deako’s beautiful designer switches are like nothing else on the market today. Deako Smart Lighting has been named the #1 Smart Lighting Control System by TecHome Builder, Top 25 Innovative IOT Companies by Entrepreneur, featured in “I Want That!” episode on DIY Network, Top 50 most promising Startups by Bloomberg, and “Changing The Way Builders Spec Light Switches” - Builder Magazine.

Mason is the fastest way to take smart devices from idea to end user. Whether building a single-use device from scratch or scaling a line of smart products, with Mason it’s 20x faster and 10x less costly to build, deploy and scale. Digital transformation is a modern requirement but operating a hardware-dependent initiative is hard – thousands of hours and millions of dollars are at stake. The Mason Smart Device Platform is the only fully managed infrastructure for developing and delivering dedicated devices. It offers flexible usage-based pricing for fleets of devices and manages the underlying complexity of all associated backend services, making software delivery on a smart product line—whether it’s a tablet, wearable or new form factor—as simple as delivering software in the cloud. This frees innovators to focus on what matters: application development, feature specification and UX. Granular access to add, remove or lock down capabilities makes it possible for highly customized products to be built as envisioned. Mason offloads hardware investment risks and logistics, including inventory procurement, warehousing and supply chain management. With options like zero-touch provisioning, devices can work perfectly out of the box without end user intervention. Remote fleet management, troubleshooting and automated software updates by Mason ensure security and positive end user experiences. Organizations of all sizes rely on Mason to bring innovations and hundreds of use cases to market without reinventing the wheel. Smarter from start to finish with Mason.™ AWARDS * 2023: Best Places to Work & Best Startups to Work For, Built In Seattle * 2022: Best Places to Work & Best Small Places to Work, Built In Seattle * 2022: IoT Health & Wellness Innovation of the Year, IoT Breakthrough * 2022: Bronze Stevie® Award - Emerging Technology, The 2022 American Business Awards® * 2021: Deloitte Technology Fast 500™, Deloitte * 2019: Tech Impact Awards, Mobile - Silver, Seattle Business magazine Follow us on LinkedIn | https://www.linkedin.com/company/mason-america/

Thrive Agritech designs and manufactures advanced lighting fixtures for indoor agriculture. We have a patent pending LED lighting system that precisely targets various photosynthetic spectrums. Many thousands of our LED lighting fixtures have been installed in some of the world's leading indoor farms. Our products are saving millions of watt-hours of energy every day in vertical farms, greenhouses and cannabis production facilities. Agritech expands beyond lighting and so do we. Our R&D team is actively involved in creating advanced sensor and communications networks to work with both human and artificial intelligence to create the optimized farm of the future.