Safari is Apple’s web browser. It comes pre-installed on every iPhone, iPad and Mac, which makes it one of the most-used browsers in the world even though it only runs on Apple hardware. Under the hood it is powered by WebKit, the rendering engine Apple builds and maintains.
Think of a browser as a translator that turns website code into the page you see. Chrome and Edge speak one dialect (Blink), Firefox speaks another (Gecko), and Safari speaks WebKit. Most of the time they agree, but now and then Safari interprets a piece of CSS or JavaScript a little differently, which is why a site can look slightly off on an iPhone. On iOS this matters even more, because Apple requires every browser, including Chrome and Firefox, to use WebKit too.
A few concrete things tend to bite. Date pickers and form inputs look different, the 100vh height unit behaves oddly when the iPhone toolbar slides away, and Safari sometimes ships a new feature months after Chrome does. A classic example is a video that plays fine on a laptop but refuses to autoplay on an iPhone, because Safari blocks sound by default to save battery and data. None of these are fatal, but you only catch them by opening the site on a real device.
That is why browser compatibility testing always includes Safari. Skipping it is a common way to ship a bug that only shows up for Apple users, and in many markets that is a large slice of your audience. It pairs with checking Chrome and Firefox so nothing is missed.
At TopDevs we test every build across Safari, Chrome and Firefox before launch, so your site looks right whether a customer opens it on an iPhone or a Windows laptop.
