Synth UI is an AI-powered SaaS platform that turns natural language descriptions into production-ready React components. Users describe the component they need in plain English (e.g. “a pricing table with three tiers and a CTA button”), and the system generates code that follows real-world patterns from a curated knowledge base of popular libraries such as shadcn/ui, Radix UI, and Tailwind-based designs. Under the hood, a modular agent architecture coordinates prompt engineering, semantic retrieval over a vector index of component examples, and structured output so that generated code is consistent and dependency-aware. The app offers real-time previews in the browser, support for multiple frameworks and styling approaches, and one-click export of deployment-ready code. Synth UI was built as a team project for the Bundeswettbewerb für Künstliche Intelligenz (BWKI) 2024, where it placed 3rd. The stack includes Next.js, the Vercel AI SDK, and a custom retrieval pipeline that balances similarity search with rule-based selection so that outputs stay close to established design systems and best practices.