Reseed

Reseed is an open-source tool for integrating static sites into subpaths. It processes all your internal links and prepends a defined subpath.

Splitting your monolith site into smaller sub-sites can simplify your workflow and cut down on your build time. For instance, you wouldn’t have to rebuild all your blog posts whenever you want to change your FAQ. You can host these sub-sites on different subpaths of the same domain. 

Reseed handles the URLs on your sub-sites, so you don’t have to worry about broken links or missing stylesheets.