What is the difference between Vanilla.js and Next.js?

The difference between Vanilla.js and Next.js lies in their purpose and complexity. Vanilla.js means there is no framework applied at all in JavaScript; the coders communicate with browser APIs directly. It allows for the manipulation of DOMs, events, or simple functionality. It works only for small projects or static content, given that more advanced functionality relies on the programmer to implement it themselves, like routing or server-side rendering.
Next.js is a powerful framework built on top of React for creating full-featured and production-ready web applications. It features built-in support for SSR, SSG, routing, and API routes that make complex application development easier. Next.js is much more suitable for modern dynamic and SEO-friendly applications. It provides performance optimizations out of the box, while Vanilla.js offers minimal structure and, when working on bigger projects, requires greater manual setup and configuration.