Chapter #97. "Does it Work on Mobile?" is Obsolete
It feels like the terms "mobile-first", "Mobile-friendly" and "responsive design" have stopped being worth mentioning—they are a given. Everything is now assumed to be responsive and mobile-first, and it's considered a breaking bug if your web app doesn't work on mobile, not to mention it being a death sentence for your SEO.
Modern frontend frameworks make it simple to build a web app or site that responds to different viewports, makes controls the right size for mobile and "gracefully degrades" (hiding elements that don't work on smaller devices). Responsive design means that the UI will adapt to different device sizes automatically, so you don't have to build a distinct "mobile version" of your product.
What's more, web apps are often better for the user than native mobile apps. This isn't a strict rule, as there are lots of reasons why you might need a native app—access to device features or heavy-duty computation or logic—but always consider...