Google Linker & React Native Firebase

[BrantApps]

I am in the process of assisting a company move all of their web & native mobile app assets over to GA4. One of the challenges in their technology landscape is the collection of 3rd party systems used for hotel bookings, restaurant bookings and e-commerce shop purchases. As such their main website hands-off to a 3rd party system hosted on a separate domain to complete a purchase. Example;

Main website: babylonstoren.com
Workshop booking: https://babylonstoren.as.me/schedule.php?appointmentType=38251887
Restaurant booking: https://booking.resdiary.com/widget/FixedSize/Babel/8730

Notice the 3 domains at play here; babylonstoren.com, babylonstoren.as.me, booking.resdiary.com

In order to track conversions across these domains I am in the process of implementing Cross-Domain measurement.

Now, for the question/discussion, I can see the work to expose the same API as the v9 firebase/analytics JS SDK is underway. Incredible effort, 👏. But this line caught my eye.

What is going to happen if duplicate my Firebase JS SDK initialisation logic into React Native Firebase and specify the gtag Google Linker config? Would the Google Linker (c.f. _gl URL parameter) start being appended to links that start in our native mobile app and load external URL (e.g. *.resdiary, *.as.me) or is this not something that can be supported on "native" (iOS/Android) apps?

Example Firebase JS SDK initialisation for cross-domain tracking

  const firebaseApp = initializeApp({
    apiKey: config.firebaseApiKey(),
    authDomain: config.firebaseAuthDomain(),
    projectId: config.firebaseProjectId(),
    storageBucket: config.firebaseStorageBucket(),
    messagingSenderId: config.firebaseMessagingSenderId(),
    appId: config.firebaseAppId(),
  })
  const analyticsInstance = fbanalytics.initializeAnalytics(firebaseApp, {
    config: {
      cookie_domain: "auto", // This is the default
      linker: {
        domains: [
          "babylonstoren.as.me",
          "booking.resdiary.com",
          "babylonstoren.com",
        ],
      },
    },
  })

[BrantApps]

Related: #6988