From Moon hotels to cattle herding: 8 startups investors chased at YC Demo Day

Investors person flocked to Y Combinator’s Demo Days for years to get their hands connected promising startups gathering chill tech. After all, the accelerator has produced immoderate of the biggest tech companies successful the world, from Airbnb and Reddit to Dropbox, Zapier and Stripe.

That’s wherefore we marque it a constituent to support an oculus connected the lawsuit to spot the astir absorbing companies from each batch. As I’ve been doing astir each 4th present that the accelerator has moved to 4 cohorts a year, I asked astir a twelve investors which startups were astir successful request astatine Y Combinator’s Winter 2026 Demo Day earlier this week.

To guarantee our database included genuinely sought-after standouts, a institution had to beryllium flagged arsenic a ‘fave’ by astatine slightest 2 antithetic task superior investors to marque the cut.

As for valuations, I’m proceeding that astatine slightest a mates startups person raised funds astatine a $100 cardinal terms tag, though notably, those startups are already bringing successful run-rate gross of $1 cardinal oregon more. Even for the little buzzy startups not connected this list, the “default” valuation this 4th seems to beryllium astir $30 million, which investors told maine is astir two-fold the existent effect marketplace average.

Without further ado, here’s the list:

Beyond Reach Labs

What it’s building: Deployable star arrays for satellites.

Why it’s a fave: The startup claims it has developed star arrays that are the size of a eating array astatine launch, but unfold to the size of a shot tract erstwhile they scope orbit. The founders accidental their strategy tin summation disposable powerfulness ten-fold portion slashing costs by 88%. Beyond Reach already has a formation planned for 2027, and says it has secured $325 cardinal successful letters of intent from starring abstraction companies.

Byteport

What it’s building: A ridiculously accelerated record transportation protocol.

Why it’s a fave: According to Byteport’s laminitis Jayram Palamadai, existing record transportation protocols similar TCP are excessively dilatory for the AI age. That’s wherefore helium built DART, abbreviated for Dynamic Accelerated Record Transfer, which tin seemingly transportation ample files astatine an mean of 10 times faster than TCP, and adjacent up to 1,500 times faster connected “reliable connections.”

Hex Security

What it’s building: Continuous AI-powered information investigating tools.

Why it’s a fave: To combat hackers utilizing AI to motorboat non-stop cyberattacks, Hex is gathering AI agents that tin enactment arsenic penetration testers, constantly probing for vulnerabilities and information gaps successful companies’ infrastructure. By automating what was erstwhile a manual process performed infrequently, Hex claims it tin forestall attacks astatine a fraction of the cost. The startup claims it has crossed run-rate gross of much than $1 cardinal successful conscionable 8 weeks, which whitethorn beryllium wherefore VC investors, arsenic 1 idiosyncratic told me, “were fighting” to put successful the company.

Grazemate

What it’s building: Autonomous drones to herd and show cattle.

 Why it’s a fave: Moving cattle connected monolithic ranches is an costly and unsafe undertaking, often involving helicopters and motorbikes. GrazeMate’s founder, who grew up connected a 6,000-head cattle presumption successful Australia, saw a mode to marque beingness easier for ranchers, truthful helium dropped retired of assemblage wherever helium was pursuing a robotics degree.

GrazeMate’s drones tin automatically usher cattle to antithetic areas of a ranch, estimation animals’ weight, writer availability and growth, and tin travel pre-specified way plans.

GRU Space

What it’s building: Permanent lunar infrastructure, starting with a edifice connected the Moon.

Why it’s a fave: “Humanity volition go interplanetary. It’s a substance of not if, but when, and the clip is now,” says GRU Space laminitis Skyler Chan, a caller Berkeley grad who antecedently built bundle astatine Tesla and worked connected NASA-funded abstraction tech.

Chan claims his startup has developed a “moon factory” that tin crook lunar ungraded into structural bricks, which helium plans to usage to physique a luxury edifice connected the satellite arsenic a “wedge” for broader lunar infrastructure. GRU’s astronomical aspirations, including its extremity to unfastened the archetypal lunar edifice by 2032, person made it 1 of the astir talked-about startups of this YC batch. The institution has already secured $500 cardinal successful letters of intent, an invitation to the White House, and adjacent a preservation from the Trump family.

Luel

What it’s building: A marketplace for human-captured information to bid multimodal AI.

Why it’s a fave: Founded by 2 UC Berkeley dropouts, Luel is gathering a information marketplace that connects AI exemplary makers with contributors who tin taxable “daily-life” activities, specified arsenic ironing oregon patient-doctor conversations, to supply audio, video and representation data. The institution claims it’s generating ARR of astir $2 cardinal wrong six weeks, fueled by precocious request from robotics and dependable AI labs.

Pax Historia

What it’s building: An alternative-history strategy crippled powered by AI.

Why it’s a fave: Pax Historia allows users to rewrite past successful a mode accepted strategy games can’t. Using generative AI, the crippled responds to infinite, analyzable geopolitical scenarios, from “What if Rome ne'er fell?” to “What if the USA took implicit Greenland?” The founders assertion the crippled presently attracts 35,000 regular users who person played astir 20 cardinal rounds.

Stilta

What it’s building: Agentic AI for intelligence spot and patent lawyers.

Why it’s a fave: Stilta’s founders assertion that patent disputes tin outgo up to $4 cardinal per case, mostly owed to manual papers reappraisal costs. The startup says its AI cause tin hunt and analyse patents crossed databases and technological literature, redeeming some clip and ineligible fees.

The company’s agents are already being utilized by IP lawyers astatine pharmaceutical elephantine Roche. For investors, different charismatic facet is that the founders hail from Sweden — caller Swedish successes similar Lovable and Legora person created thing of a “halo effect” astir companies from the region, 1 VC capitalist said.