Lennart Jörgens discusses the integration of TypeScript in Gatsby, highlighting the ability to use TypeScript for gatsby-config and gatsby-node files since GatsbyConf 2022, enhancing the developer experience with type safety and improved IDE support. The post offers a step-by-step guide on setting up a new Gatsby project using TypeScript, including initializing the project via CLI, configuring gatsby-config.ts and gatsby-node.ts, and creating custom nodes. It emphasizes type safety through the use of TypeScript types like GatsbyNode and PageProps and explores styling with vanilla-extract, a CSS-in-TypeScript solution that ensures type-safe CSS writing. The article encourages users to explore further resources like the How-To Guide on TypeScript in Gatsby and a real-world example project, gatsby-starter-tmdb, for more comprehensive learning.