Deferred Deep Link: What It Is, How It Works and Is Used in Development

What Is Deferred Deep Link?

Deferred Deep Link is a type of deep link that works in two stages: first the user follows the link before the app is installed, then the system restores the context after installation completes. A regular deep link opens the app only if it is already installed, while deferred saves all transition parameters and passes them on first launch.

The technology has become especially in demand with the growth of mobile marketing, where ad campaigns often target users who have not yet installed the app. Without deferred deep link, each such transition would simply end with the app downloading without any context — the user would land on the main screen instead of the target one.

Difference from Regular Deep Link

A regular deep link opens target content in an already installed app. If the app is not installed, the browser displays an error. Deferred Deep Link works through an intermediate server that redirects the user to the store, and after installation notifies the app of the saved parameters. Thus, a deferred link does not require the app to be pre-installed and provides an end-to-end user journey from ad to content.

How Deferred Deep Link Works

The deferred deep link processing consists of three stages. At the first stage, the user follows the link — the server determines whether the app is installed. If not, it generates a unique session identifier, saves the transition parameters, and redirects the user to the App Store or Google Play with this identifier.

At the second stage, the user installs the app from the store. After installation and first launch, the platform SDK contacts the server, passes the device identifier, and receives the saved transition parameters. At the third stage, the app processes the received data and automatically redirects the user to the target screen.

Deferred Link Lifecycle

Various mechanisms are used to save parameters between the link click and installation. On iOS, this is iCloud Keychain or clipboard; on Android, it is the Install Referrer API. Firebase Dynamic Links uses a combination of browser localStorage and the store referral link to pass the session identifier. Branch.io uses its own protocol with data backup across multiple storages.

Deferred Deep Link in iOS

In iOS, deferred deep link is implemented through a combination of Universal Links and Shared Web Credentials. When a user follows a Universal Link to the app’s website, Safari saves the transition parameters in iCloud Keychain associated with the app’s domain. After installing the app from the App Store, iOS checks for saved data and passes it to the app on first launch.

Apple does not provide a built-in API for deferred deep link — implementation is entirely left to third-party SDKs. Firebase Dynamic Links uses a passive deferred mechanism, where data is saved in browser cookies and restored via a redirect to a special URL on the app’s first launch.

Limitations on iOS

Starting with iOS 14, Apple tightened privacy rules, which affected deferred deep link mechanisms. Clipboard can no longer be used to read data without explicit user permission. iCloud Keychain also has data size limits — no more than 4 KB per write. This makes server-side solutions with a unique session identifier the preferred method for passing context.

Deferred Deep Link in Android

Android provides more flexible options for deferred deep link through the Install Referrer API. When a user follows a link to Google Play, the store captures the referrer — a string with transition parameters. After installation, the app receives this string through the Install Referrer API and extracts the target context from it. This is the most reliable deferred deep link mechanism on Android.

For apps distributed outside Google Play, Android supports a referral BroadcastReceiver. The developer can send a custom Intent with parameters after installation, and the app will receive it through a BroadcastReceiver registered in the manifest. However, this mechanism is less reliable as it depends on the installer implementation.

Install Referrer API

The Install Referrer API provides information about the installation source, including referrer URL, click time, and install time. The maximum referrer string length is 8 KB, which is sufficient for passing all necessary deep link parameters. The API is available on devices with Google Play Store version 8.3.73 and higher, and is supported on Android 5.0 (API 21).

Implementation via Firebase Dynamic Links

Firebase Dynamic Links is the most popular free tool for implementing deferred deep link on both platforms. Firebase automatically handles all stages of the deferred transition: redirecting to the store when the app is absent, storing parameters on the Firebase server, and passing them to the SDK on the app’s first launch.

To implement, simply integrate the Firebase SDK into your project, create a Dynamic Link through Firebase Console specifying the deep link and campaign parameters. The Firebase SDK is automatically called when the app launches and checks for an incoming Dynamic Link via the getDynamicLink() method.

Processing Setup Example

Example of processing a deferred Firebase Dynamic Link in an Activity in Kotlin. The code works identically for cold start and warm start when the app launches.

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        checkDeferredLink()
    }

    private fun checkDeferredLink() {
        FirebaseDynamicLinks.getInstance()
            .getDynamicLink(intent)
            .addOnSuccessListener link ->
                val deferredLink = link?.link.toString()
                if (deferredLink.isNotEmpty()) {
                    navigateToContent(deferredLink)
                }
            }
    }
}

The getDynamicLink() method returns a PendingTask with a DynamicLink object. If the app was installed after following the link, the listener will receive data with parameters. If the app was already installed before the transition, the method will return the same data as with a regular deep link. The minimumAppVersion flag in the link parameters allows setting the minimum app version for processing.

Benefits and Limitations of Deferred Deep Link

Deferred Deep Link provides significant advantages for marketing campaigns: the user receives target content after installation without additional actions, which increases conversion and retention. For referral programs, deferred links allow unambiguously linking an invitation to installation and new user actions.

However, the technology also has limitations. Deferred deep link does not work in browsers that block third-party cookies, and on iOS from version 14 additional configuration is required for iCloud Keychain. Moreover, between the link click and installation several days may pass, and not all SDKs guarantee data preservation for such a period.

When to Use Deferred Deep Link

Deferred deep link is mandatory for ad campaigns targeting new users, email invitations, and referral programs. For already installed users, a regular deep link is sufficient. If the app does not use marketing campaigns or referral mechanics, deferred deep link is not needed — Universal Links and App Links are enough.

When choosing an implementation, consider cost: Firebase Dynamic Links is free but has limited analytics. Branch.io and AppsFlyer provide advanced attribution but require a subscription. For small projects, Firebase is the optimal solution; for enterprise with dozens of ad channels, commercial MMPs are the choice.