Responsive design – what is it and why do you need it? Responsive design is a way of designing and developing websites with a smooth, fluid layout, so that the pictures and other components of the site are able to adapt to the screen where site is viewed. This is a method that is commonly used to generate content on the internet across assorted devices flawlessly. It usually includes sending to the site once, then the URL serves the content directly to the device asking for it. The device can vary greatly, anything like a tablet, laptop, cell phone, TV, or other mobile device.