The key role of a back-end developer is to ensure that the data requested by the front-end system is delivered and/or saved. He/she creates the core computational logic of a website.

Back-end technologies usually consist of programming languages like PHP, Ruby, Python, etc. To make them easier to use they are usually enhanced by frameworks (i.e: Ruby on Rails) that make development faster and easier to collaborate on.

CMS: Today, websites are often built on top of a CMS (Content Management Systems). These allow the content manager or author, who may not know HTML, to manage the creation, modification, and removal of content from a website without needing the expertise of a Web developer.  Platforms such as WordPress and Squarespace provide CMS templates to create simple websites. For more complex front and back end needs, the back end developer creates a custom CMS for the client.

–  Anna Pinkas