GitHub Pages only supports building sites with Jekyll[0].

According to the Netlify documentation[1], it looks like they support any/most tools, including Jekyll, Grunt, Middleman, Roots, Hugo, etc.

[0]: https://help.github.com/articles/using-jekyll-as-a-static-si...

[1]: https://www.netlify.com/docs/continuous-deployment

We have a Metalsmith static site that requires "npm build" to build and Netlify seemed to figure it out automatically. Pulls directly from GitHub, built, deployed, SSL with LetsEncrypt. All for free.

Very nice service.