Too Long; Didn't Read
A Headless CMS is a “Content Repository” that makes content accessible to any platform via an API. The intended consumption of this content is by devices in a raw structured format, such as HTML or JSON, and isn't meant for human consumption until rendered on the end device. Marketing and editorial teams can create content within the editor interface of a headless CMS (similar to how they would with Wordpress or Joomla) and the engineering team can define how and where this content can be delivered.