What is an install referrer?

Most commonly used to refer to Google Play’s Install Referrer API, an install referrer—more generally—is a string of unique characters used to attribute mobile app installs on Android devices and measure ad performance.

Glossary
What is an install referrer?

The definition of install referrer

An install referrer is an Android-specific string of unique characters used to deterministically attribute installs to ads for marketing purposes. Install referrers are used by app marketers to measure ad performance on Android devices. 

The term install referrer is most commonly used in reference to the Google Play Install Referrer API, which we cover below. Other Android app stores, like Samsung’s Galaxy Store, Huawei’s App Gallery, and Xiaomi’s MIUI, however, also support install referrer attribution. Meta also offers an install referrer to provide marketers with enhanced visibility into Meta Android Campaigns.

Install referrers are highly accurate and highly valuable to attribution, particularly within the context of the privacy-era. As they do not require persistent device-ID access—Google Advertising ID (GAID)—for the purposes of attribution, but still offer reliable attribution, mobile marketers on Android commonly use the install referrer in the absence of the GAID, or vice versa.

Note: Adjust considers referrer matching and advertising ID or device ID matching as equal methods for attribution. But, if a click has both referrer matching and advertising ID/deviceID matching available, Adjust sets the method as referrer matching.

What is the Google Play Install Referrer API?

The Google Play Install Referrer is an API utilized to retrieve referral content and information from the Google Play Store—for the purpose of linking clicks on Play Store app pages to app installs. This API has become essential in the Android ecosystem due to its ability to provide accurate data while respecting privacy, enabling assessment of the effectiveness of marketing channels on critical key performance indicators (KPIs)—including return on ad spend (ROAS)—and the ability to perform campaign optimization.

In short, by using the API, marketers gain a clear picture of user acquisition sources.

install referrer

How does the Play Install Referrer API work?

Referrers all work more or less the same way. A user clicks an ad and parameters are added to the link, which are sent via the relevant app store to the attribution provider when the app is opened, via an API. For the Google Play Install Referrer, when an app is installed, the Play Store sends this information (the referral content) to the mobile measurement partner (MMP). 

This multi-step process is best understood when grouped under the following three main action points, using the Google Play Install Referrer API as the example:

  1. User clicks on an ad
    This process begins when a user clicks on an ad. The MMP generates a unique identifier (reftag) and appends it to the link/URL, and redirects the user to the Google Play Store, which captures and temporarily saves that information.

  2. User downloads and opens app, triggering MMP’s SDK to request referral content
    Following redirection, the user downloads the app. Upon opening, the MMP’s SDK records an install and requests information, aka the referral content, from the Play Store.

    The referral content collected will depend upon the parameters placed, but can include:

    • The referrer URL of the installed package.
    • The timestamp of when the click occurred.
    • The timestamp of when an app install began.
    • The app’s version when the app was initially installed.

  3. Google Play sends referral content to MMP for attribution purposes
    The Google Play Store then shares the referral content with the MMP so that the MMP can match information from the ad click and install to accurately award attribution. This attribution data is available within the MMP’s dashboard so marketers can perform campaign analysis and make informed decisions.

User flow for attribution via Google Play Install Referrer with Adjust:

As displayed on the image above, the specific flow for Google Play Install Referrer attribution looks like this: 

  1. User clicks on an ad and is redirected to the Adjust server.
  2. Adjust generates a unique identifier (reftag) and appends it to the tracker URL.
  3. Adjust redirects the user to the Google Play Store.
  4. The Play Store captures the reftag and temporarily saves it. 
  5. User download the app.
  6. The Adjust SDK requests information from the Play Store about the install.
  7. The Play Store shares information with Adjust—based on the parameters set—via the install referrer API.
  8. Adjust matches this information to award attribution.

Will Google’s Privacy Sandbox on Android affect Install referrers?

No, not at the present moment. Google states on its website for Android Developers that based on current plans, “...the Privacy Sandbox APIs will not impact the functionality provided by the Play Install Referrer.”

What is the Facebook install referrer/Meta install referrer?

Since the deprecation of Facebook’s Advanced Mobile Measurement program (MMM), Meta has utilized the Google Play Install Referrer and gone on to introduce its own Meta install referrer. Meta’s install referrer does not replace use of the Google Play Install Referrer, but aims to provide a fuller picture to clients advertising on Meta properties, including Facebook—to fill measurement gaps when working on Meta Android App Ads campaigns.

Meta install referrer expands on the capabilities of the Play Install Referrer by enabling measurement on view-through installs, not only same-session click-though installs. 

Read more about Meta install referrer and Adjust.

Adjust and install referrers

At Adjust, we’re evolving to incorporate and offer robust new measurement methods that gain insights from aggregated data sources beyond device-ID based attribution. As part of our holistic, privacy-centric attribution framework, install referrers are used to match installs to clicks where available. This includes Google Play Install Referrer (for Play Store and third-party app stores), Samsung referrer, Meta install referrer, and more. Learn more about Adjust’s attribution methods and how we match your app users to the source that drove their install 

Request a demo today to see first-hand how Adjust can power your marketing with the measurement solutions you need to hit—and exceed—your growth goals.

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