CMS developers are in charge of both back-end and front-end development, which includes creating popular CMS themes and plugins such as WordPress themes and plugins. They can code in a variety of languages, including PHP, HTML5, CSS3, and JavaScript. They're also quite skilled in terms of aesthetics and website front-end ergonomics. They aren't the best designers, but they do a good job of replicating the designers' input with their programming talents.