The {:link, link} message a screen receives when the app is opened by a URL: a link tapped in another app, a QR code read by the camera or a scanner app, adb shell am start -a android.intent.action.VIEW -d 'myapp://…', xcrun simctl openurl booted 'myapp://…'.

def handle_info({:link, %{url: url}}, socket) do
  case URI.parse(url) do
    %URI{scheme: "myapp", host: "thread", query: query} when is_binary(query) ->
      params = URI.decode_query(query)
      {:noreply, Mob.Socket.push_screen(socket, MyApp.ThreadScreen, params)}

    _ ->
      {:noreply, socket}
  end
end

Any app on the device can open one, with anything in it. Parse it and check what it asks for before acting on it.

Fields

• :url — the URL as the platform handed it over.
• :source — :launch when it opened the app, or arrived while the app was starting: it was held until the root screen had mounted. :running when the app was already running.

Where it is delivered

To the process registered with register/1 while it is alive, otherwise to the screen currently showing. A link that launches the app arrives once the root screen has mounted, exactly once. A screen that defines its own handle_info/2 clauses needs one for {:link, _} (or a catch-all) to receive links without crashing.

Which links open the app

A custom scheme is declared at build time: config :mob_dev, url_schemes: ["myapp"] in mob.exs makes the native build (mob_dev 0.7.12 or later) add an intent filter to the Android main activity and a CFBundleURLTypes entry to the iOS bundle. A change needs a native rebuild. On Android the main activity must be android:launchMode="singleTask", or a link opened from another app's task starts a second activity there; the build refuses url_schemes without it.

Native code hands each URL to mob with mob_deliver_link(const char *url) (mob_beam.h, both platforms): the generated Android MainActivity forwards ACTION_VIEW intents through MobBridge.nativeDeliverLink, and the iOS SceneDelegate forwards its URL contexts. An app whose native files were generated before mob_new 0.6.4 adds those calls itself; see "Deep links" in the device capabilities guide. Like notifications, every link passes through the :mob_screen router, which keeps the one that launched the app until the root screen has mounted; see decisions/2026-10-03-deep-link-delivery.md.