Explore full-stack type safety in modern web app development through a conference talk that bridges Java and TypeScript. Learn to build a reactive web application using the open-source Hilla framework, combining a Spring Boot backend with a Lit-frontend. Discover how to extend type-safety from server to client, create reactive properties, implement endpoints, manage component lifecycles, and bind data to forms. Follow along as the speaker demonstrates building a chat feature, showcasing the seamless integration of Java and TypeScript for enhanced development efficiency and code reliability.