The YC 2025 Summer Demo Day featured over 160 startups, with a significant focus on AI-native applications and infrastructure. Key startups include Autumn, which integrates AI pricing with Stripe, and Dedalus Labs, which automates AI agent infrastructure. Keystone, led by Pablo Hansen, targets AI-driven software bug fixes, while Solva automates insurance claims. RealRoots offers AI-based social matching for women, and Pingo AI provides language tutoring. These developments underscore a shift towards AI-native solutions, highlighting the growing importance of infrastructure and vertical applications in the AI sector.