What they are and why you need them Deep linking lets a URL open a specific screen inside your native app instead of the mobile browser. There are three approaches: custom URI schemes, Universal Links (iOS), and Android App Links.
Custom URI schemes like myapp://product/123 work but come with two serious problems: they can be intercepted by any app that registers the same scheme, and if the app isn't installed, the user sees a broken "This site can't be reached" error with no graceful fallback.
Universal Links and App Links solve both issues. They use standard https:// URLs — the same ones on your website — and are cryptographically tied to your domain via a verification file that only you can host. If the app is installed, the OS routes the URL directly to it. If not, the browser opens your website instead.