sitio
A static site generator that works with imperative code instead of declarative templates and directory structures. It assumes nothing and can be used to transform anything into HTML pages.
It uses React so it can be used to generate single-page apps too if you want – and normal sites that work like single-page apps.
It also provides helpers for reading Markdown files, like all static site generator does.
A long time after creating this and breaking it while trying to add too many features at once I realized Gatsby also had an imperative engine underlying the default declarative interface that could be used and it was pretty similar to sitio. That both made me happy to have arrived at the same results of such an acclaimed tool and sad for the same reason, as Gatsby is the worse static site generator ever created considering user experience.