Docusaurus

Docusaurus is a static-site generator, available free and open source under an MIT license from Meta Open Source, used to build a single-page application with fast client-side navigation, leveraging React to make the site interactive. It provides out-of-the-box documentation features but can be used to create any kind of site (personal website, product, blog, marketing landing pages, etc).

Docusaurus starts at $0.