I’ve been building website and web applications for a number of years. Making front end responsive site is a large part of my experience and throughout the years I have heard the same phrase over and over: 'mobile first'. Whether that’s designing or building, the community consensus has been do it all 'mobile first'.
Mobile has become the first port of call for most people when browsing the internet, there is no doubt about that. However I believe we are in a time of ‘platform ambiguous’ browsing and that is what we need to design and build for. Not start with the most popular way people browse (mobile) and figure things out from there.
You can build a stunning site starting with desktop and moving down to tablet and mobile. It demands ingenuity from the developer and designer, stripping back the things that aren’t absolutely necessary when the platform can no longer support it or finding innovative ways of including those elements.
Inversely, moving from mobile to desktop, we see alien elements added to fill the white space that appears when increasing the format. Everyone knows the tell tale signs… boxes stretched far beyond their intended capacity, font sizes that look clumsy on the page and iconography that means very little to the standard user.
Either approach done badly will cause a sub par looking site and I will concede that often a bad desktop first site will look worse than a bad mobile first one. However we live in a world where the public demands everything from web applications and we should strive to offer that. I believe to get the best looking application you need consider all platforms and build accordingly.
Give your designers the freedom and the space to add everything they want. Then introduce limitations, the smaller formats, it is a great tool to help you edit and optimise all designs. Then work hard to make sure all platforms look and perform perfectly.