Next.js is described as 'gives you the best developer experience with all the features you need for production: hybrid static & server rendering, TypeScript support, smart bundling, route pre-fetching, and more. No config needed' and is a static site generator in the development category. There are more than 10 alternatives to Next.js for a variety of platforms, including Self-Hosted solutions, Mac, Windows, Linux and Online / Web-based. The best alternative is Jekyll, which is both free and Open Source. Other great apps like Next.js are React, Hugo, Gatsby and Eleventy.
Jekyll is a simple, blog aware, static site generator. It takes a template directory (representing the raw form of a website), runs it through and Liquid converters, and spits out a complete, static website suitable for serving with Apache or your favorite web server.
verless (pronounced like serverless) is a Static Site Generator designed for Markdown-based content with focus on simplicity and performance. It reads your Markdown files, applies your HTML templates and renders them as a website.