Although DSLs have been around for a long time, the lack of knowledge of how to program with them is a significant barrier

People find DSLs valuable because a well-designed DSL can be much easier to program with than a traditional library.

DSLs come in two main forms: external and internal. An external DSL is a language that's parsed independently of the host general purpose language: good examples include regular expressions and CSS. External DSLs have a strong tradition in the Unix community. Internal DSLs are a particular form of API in a host general purpose language, often referred to as a fluent interface. The way mocking libraries, such as JMock, define expectations for tests are good examples of this, as are many of the mechanisms used by Ruby on Rails. Internal DSLs also have a long tradition of usage, particularly in the Lisp community.

DSLs are small languages, focused on a particular aspect of a software system. You can't build a whole program with a DSL, but you often use multiple DSLs in a system mainly written in a general purpose language

What is a headless CMS?A headless CMS is any type of back-end content management system where the content repository “body” is separated or decoupled from the presentation layer “head.” Content that is housed in a headless CMS is delivered via APIs for seamless display across different devices.