Inertia.js lets you build the public side of a website as a React, Vue or Svelte app while keeping the routing and data on the server. Routes return page components with their data instead of HTML, so there is no separate API to build. October CMS 4 is built on Laravel, so Inertia's Laravel adapter works with it directly. October CMS provides the admin panel, plugins, Tailor and the data, and Inertia with React and Vite renders the website in place of an October CMS theme.