When you long-press the reload button in Safari for iOS and select “Request Desktop Website,” all you’re doing is changing your user agent. This doesn’t do anything for most websites, because most websites offer their mobility via responsive CSS. Responsive CSS pays no attention to the user agent — instead it looks at the viewport width. And in Safari there’s no way to customize your viewport width. That’s where the Desktop Browser for iOS comes in. It somehow modifies things so responsive websites think you’re using a browser that’s wider than it really is. Desktop Browser might be achieving this by simply removing the viewport meta tag from the head of the document. That tag often looks something like this:

<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1" />

The more I think about it, that’s probably how Desktop Browser is achieving this.1 However it’s doing it, it works consistently, and I love it.

  1. When you visit a viewport revealer in Desktop Browser that programmatically shows your viewport width, it registers as the correct one (375 pixel width on an iPhone XS). That’s why I don’t think Desktop Browser is spoofing the viewport width. ↩︎