It's a list of material about consuming Magento 2 in another application, for example a single page web application, progressive web app or even mobile application
It's an ecommerce framework written in PHP. It's readily extensible, and quite well built. See
It means that the application itself is not responsible for rendering the end page to the user, but rather only for supplying the data over network connection (usually REST API or some such)
- https://developers.google.com/web/fundamentals/architecture/app-shell - A description of the application shell architecture; a common design for headless applications.
- https://shop.polymer-project.org/ - An example shop implementing a Polymer based application shell
- https://alankent.me/2016/12/14/headless-magento-and-extensions/ - Alan Kent (Magento Architect) personal thoughts on headless Magento 2.
- CMS Api In Mage2 http://davidmanners.de/cms-api-in-mage2
- Brainstorming repo for improving the Mage2 API to make headless happen https://github.com/ishakhsuvarov/going-headless
- PHP wrapper for Magento 2 APIs https://github.com/KickAssCommerce/magesdk