The 6 most exciting AI vibe coding tools from startups in Y Combinator's summer cohort Demo Day (www.businessinsider.com)

Y Combinator’s summer Demo Day showcased a surge of “vibe coding” startups — tools that let people write software by chatting with AI or building agentic workflows with natural language. YC execs say the trend is mainstreaming: roughly a quarter of a recent batch produced 95% of their code with AI, and investors and YC partners are already publishing best practices. The cohort included companies ranging from Bitrig (AI-generated iOS apps in Swift) and Floot (14,000-user web-app builder) to Okibi (natural‑language agents that talk to internal systems), Stagewise (browser-based visual frontend tooling), Vibe Code Go (mobile vibe coding), and VibeFlow (prompt-to-full-site generation with backend logic). For the AI/ML community this signals both opportunity and friction: massive developer-productivity gains and a new startup archetype attracting funding and tooling ecosystems, but also limitations — model-generated code can be error-prone and struggles on complex engineering problems. Technically, the emerging stack spans model-driven code generation, agent orchestration for internal APIs, browser-integrated low-code UIs, and mobile-first developer interfaces. The pattern implies accelerated prototyping cycles, shifts in frontend/backend roles, and rising demand for robust verification, retrieval-augmented generation, and safety/observability layers to make AI-generated software reliable in production.