YC Demo Day is held every time a new season begins. On Tuesday, the Spring 2026 cohort was announced. This includes defense technology, robotics, AI infrastructure, developer tools, and of course the AI agents themselves.
TechCrunch spoke to eight investors to determine the hottest companies in this group. Both companies they had their eye on and startups they heard other VCs weren't interested in enough. This list primarily consists of companies marked by at least two investors as the most talked about companies in the batch.
That excitement led to larger rounds and higher price tags for some companies. Just when we thought YC's valuation couldn't go any higher, it exceeded all expectations. This batch included at least two startups with valuations of more than $175 million. Investors were also clear that they were willing to pay a premium for proven repeat founders.
We've listed the standouts below, arranged alphabetically.
mother of 9
What we're building: An AI-powered anti-drone system
Why we love it: The conflict between Russia and Ukraine has shown how deadly small unmanned aircraft can be, with the systems currently accounting for about 80% of casualties. Existing counter-drone solutions are expensive and often ineffective at interfering with low-flying drone swarms. 9Mothers claims to have developed a more “affordable” robot that can track and kill drones flying at 60mph.
The startup, founded in 2024, has already recorded sales of $1.6 million, with single deals expected to grow to $35 million later this year. The company has also promised investors that it can reach a $1 billion contract pipeline. That potential, coupled with a clear need, motivated one VC to invest at a valuation of $200 million or more, one VC said. At this valuation, 9 Mothers is not only the most valued startup in the group, but could also be one of the most valuable startups in YC's history. (Nine mothers did not respond to our requests for comment.)
Agra Institute
What we're building: A tool that provides a digital twin environment for testing AI agents.
Why we love it: AI allows software engineers to generate more code much faster. That code needs to be tested, but traditional test environments, also known as sandboxes, can't be created fast enough to keep up. Arga Labs solves this bottleneck by instantly spinning up a “digital twin” of a company's software, allowing AI agents to safely test code before it reaches production.
Adiarante
What we're building: A mobile MRI clinic for early cancer detection
Why we love it: We know early detection saves lives, but our health system doesn't have enough MRI machines to regularly test everyone. They are too expensive, costing millions of dollars to purchase and tens of thousands of dollars annually to maintain. Adiarante is trying to solve this problem. The company says it has designed a compact MRI unit that can be transported in small trucks. Adialante's business model is to bring these machines into clinics and charge $250 per scan. The company's big but worthy ambition is to transform MRI scans from being reserved for symptomatic patients to being a routine annual test.
Compliant
What we're building: Physical product compliance management
Why we love it: Shipping physical goods across borders can be very complicated. There are so many regulations, including ensuring proper translation when selling into the EU and ensuring that beauty product labels comply with each country's labeling requirements. Complir wants to make this easier by creating an AI agent that allows companies to manage and monitor compliance, risk, regulatory changes, and generate the necessary documentation and product labels for products shipped internationally. It's no surprise that investors have taken notice of companies like this. Its products address specific pain points for many businesses that AI could help with.
express delivery
What we're building: Satellites that can safely return products manufactured in space to Earth.
Why we love it: Space is the perfect environment for manufacturing certain pharmaceuticals, semiconductors, and 3D printed human tissues and organs, thanks to its microgravity and near-perfect vacuum. Manufacturing in space could be the future, and Dispatch wants to be a part of it by developing vehicles that can withstand heat and bring products back to Earth. Unlike many space capsules, which burn out or be discarded after one use, Dispatch designs its vehicles to be refurbished and sent back into space multiple times. Venture capital is betting that manufacturing in space is closer than we think, and that there could be great value in handling the transportation of those products.
light sprint
What we're building: Tools that allow non-engineers to ship and build features without writing code.
Why we love it: Lightsprint allows anyone, with or without coding experience, to build and ship production functionality for their applications. Previously, if a change needed to be made to an application, product managers had to wait for engineers to fix it. But Lightsprint wants to instead be a tool that product managers use directly. Users describe what they want to fix or adjust, choose from visual options how they want their changes to appear, and the Lightsprint AI agent builds it for them. Once the product manager is satisfied, the new code is reviewed, approved by engineers, and merged with existing code, allowing the company to officially ship the new feature.
trick
What we're building: Tools to automate website building and marketing growth
Why it's popular: Our sources weren't kidding about Ploy's popularity. Shortly after we added the company to our list, Ploy announced a healthy $27 million seed round led by First Round and Y Combinator. What about the lottery? Ploy was founded by Bryant Chou, co-founder and former CTO of Webflow, a drag-and-drop website builder (last valued at $4 billion). Ploy takes website creation to the next level by automatically generating landing pages, writing marketing copy, and launching campaigns. The startup's AI agent continuously improves website content with the aim of accelerating inbound growth. In this way, the startup promises to eliminate the need for large marketing teams.
Sotheby's
What we're building: An AI-powered platform that finds software issues and generates fixes.
Why we love it: Sazabi was founded by Sherwood Callaway, an iteration of YC's founder. Resume also includes being an a16z scout, Brex and 11x employee. That experience alone makes him a popular investor. But venture capitalists are also interested in the product, a tool that helps find and flag problems in software production systems. Sotheby's integrates with Slack to communicate with your team via the chat app. Runs log analysis (scripts that the software creates while running) to determine why a problem occurs in production, and allows users to generate and submit a fix for the problem with one click.
Silmarillion
What we're building: AI security infrastructure
Why we like it: Autonomy is a hot area for investors right now. Investors are funding countless companies that put AI agents to work in critical parts of their businesses. Silmaril is working to prevent agents from being hacked through “prompt injection.” This means that the public parts of the agent cannot be manipulated by hackers through prompts, emails, or other documents. Silmaril's agents autonomously investigate new threats to agents and applications, and when they discover a threat, they autonomously retrain the firewall to become resistant to it.
super set
What we're building: A platform that allows developers to run at least 100 coding agents simultaneously.
Why we love it: Coding agents have completely invaded the world of software development. As they proliferate, you need a way to manage them in one space. That's what Superset aims to do. This tool allows developers to launch and manage over 100 coding agents at once. Command-line interface (CLI) agents such as Claude and Cursor can run on the platform, and each agent runs in its own small workspace, so there are no conflicts between agents. This tool can also be opened in an integrated development environment (IDE) such as VS Code or Cursor.
tasklet
What we're building: AI agents that perform tasks
Why we love it: The company's premise is simple, but has the potential to be incredibly effective. Tasklet is an AI agent that connects to APIs of various business applications such as Slack, Outlook, and Google Drive. Users can use natural language to instruct these apps to perform related tasks.
Users can ask workflows to automatically process and perform tasks such as sorting emails or retrieving reports. It also runs continuously. This means that the agent continues to work even if the user closes the tab. Not only can you write and run your own code, but you can also build interfaces.
Some investors have noted that they are moving away from investing in horizontal tools like this, but Tasklet appears to be bucking the trend. It positions itself as a place where users go to give commands rather than opening applications individually. Perhaps there is a future where this becomes the default way some people interact with software.
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