Do people use Next.js as an API server too? In all the projects I've joined, we've only used Next.js as a static frontend framework and dev tool built on top of

Do people use Next.js as an API server too? In all the projects I've joined, we've only used Next.js as a static frontend framework and dev tool built on top of React. We never touched the SSR feature, just used it as a static site generator, and didn't bother implementing any APIs in Next.js. I can't imagine someone can implement a robust code base while mixing frontend and backend code in that messy folder structure.