Adaptive web design

This article needs to be updated. Please help update this article to reflect recent events or newly available information. (September 2018)

Adaptive web design (AWD) promotes the creation of multiple versions of a web page to better fit the user's device, as opposed to a single static page which loads (and looks) the same on all devices or a single page which reorders and resizes content responsively based on the device/screen size/browser of the user.

This most often describes the use of a mobile and a desktop version of a page (or in most cases, the entire website), either of which is retrieved based on the user-agent defined in the HTTP GET request, which is known as dynamic serving. Adaptive web design was one of the first strategies for optimizing a site for mobile readability, the most common practice involved using a completely separate website for mobile and desktop, with mobile devices often redirected to the mobile version of the site served on a subdomain (often the third level subdomain, denoted "m"; e.g. http://m.website.com/; and/or URL parameters like &app=m&persist_app=1 used on YouTube). Today the use of two separate static sites for mobile and desktop viewing is being largely phased out, with Server-side scripting instead utilized to serve dynamically generated pages or to dynamically decide which version of a static page to serve, although the use of independent sites for mobile and desktop can still be frequently observed. While many websites employ either responsive or adaptive web design techniques, the two are not mutually exclusive, and best practices for the most universally readable designed content employ a combination of the two techniques to support a complete spectrum of hardware and software.^[2]

The existence of separate front ends allows clients who experience technical issues with either to fall back to another, with the chance that the issue does not occur.