Elm is a domain-specific programming language for declaratively creating web browser-based graphical user interfaces. Elm is purely functional, and is developed with emphasis on usability, performance, and robustness.What's a elm? Elms are deciduous and semi-deciduous trees comprising the flowering plant genus Ulmus in the plant family Ulmaceae. The genus first appeared in the Miocene geological period about 20 million years ago, originating in what is now central Asia. ... Elms are components of many kinds of natural forests.How does Elm work? Elm uses an abstraction called ports to communicate with JavaScript. It allows values to flow in and out of Elm programs, making it possible to communicate between Elm and JavaScript. Elm has a library called elm/html that a programmer can use to write HTML and CSS within Elm.Is Elm a good language? Elm is a functional programming language for building front-end web applications. It brings the best of both worlds when it comes to building highly robust applications with ease.Is Elm still being developed? There are no “developers” of Elm. There is only Evan. If there would have been 2, Evan would have been free to develop 0.19 while the second developer could have maintained 0.18 . Since there is only one developer, 0.18 remained unmaintained.