Contained within is an overview of Headless CMSs, a comparison to Traditional and Hybrid systems, and the advantages of Headless — including how the front-end flexibility supports popular JavaScipt frameworks. Also included is a step-by-step guide to building a single page application (SPA), progressive webapp (PWA) from scratch, after which readers will have created a sample web project using React for the frontend and Jahia’s GraphQL API to access back-end headless content.