Y Combinator wrapped its Summer 2025 Demo Day last week, and the investor buzz is already crystallizing around nine breakout companies. From AI billing infrastructure to counter-drone missiles, this batch signals a clear shift from simple "AI-powered" products to sophisticated agent platforms and specialized tooling. We spoke with YC-focused investors to identify which startups are generating the highest investment demand.
The numbers tell the story of this batch's ambition. Y Combinator showcased over 160 startups during its Summer 2025 Demo Day, but nine companies are already standing out in investor conversations. The shift is unmistakable - instead of pitching "AI-powered" features, these founders are building the foundational infrastructure that'll power the next wave of AI applications.
Autumn is tackling one of the industry's messiest problems: AI startup billing. Anyone who's tried to implement usage-based pricing on Stripe knows the pain. "Managing complex AI pricing on Stripe is a time-consuming, manual process," according to TechCrunch's analysis. Autumn's open-source infrastructure is already handling payments for hundreds of AI apps and 40 YC startups, positioning it as the billing backbone for the AI economy.
Meanwhile, Dedalus Labs is building what they call "Vercel for AI agents." Just as Vercel simplified web deployment, Dedalus automates the complex infrastructure needed for AI agent development. The platform handles autoscaling and load balancing, cutting deployment time from hours to clicks.
But it's not just infrastructure plays capturing attention. The standout revenue story belongs to 17-year-old Raghav Arora's Getasap Asia, which he founded at age 14. The tech-enabled distributor delivers supplies to Southeast Asian retailers in under eight hours and has already generated millions in revenue. Sources tell us Getasap Asia's valuation was among the highest in the entire batch, with General Catalyst leading their recent round.
The AI debugging space is heating up too. Twenty-year-old Pablo Hansen's Keystone has built an AI engineer that automatically finds and fixes production bugs. The company has already turned down a seven-figure acquisition offer, according to Hansen, while serving clients like Lovable.
