Install referrer

What is Install referrer?

Install referrer is an Android attribution mechanism that captures the source of an app install by passing a unique string through the Google Play Store at the moment a user clicks an ad or referral link. The string contains campaign parameters, referral source identifiers, and any custom tracking data appended by the marketer. When the app is installed and opened, this string is retrieved from the Play Store and sent to the attribution partner for matching against the original click.

How it works

When a user clicks an ad or a tracking link for an Android app, the click URL includes a referrer parameter containing encoded campaign data. Google Play Store stores this referrer string and associates it with the user's install.

Referrer Parameter Structure

The referrer string typically contains UTM parameters such as utm_source, utm_medium, utm_campaign, utm_term, and utm_content. Marketers and ad networks also append custom parameters to identify specific publishers, creatives, or placements. For example, a referrer string might look like: utm_source=network_name&utm_medium=cpc&utm_campaign=summer_sale.

Retrieval and Attribution Matching

Once the app is installed and launched for the first time, it queries the Google Play Install Referrer API to retrieve the stored referrer string. The app's SDK forwards this string to the mobile measurement partner (MMP). The MMP then matches the referrer data against recorded clicks to attribute the install to the correct campaign, channel, and creative.

Google Play Install Referrer API

Google provides the Install Referrer API as the standard programmatic interface for retrieving this data. It replaced the older broadcast receiver method, delivering more reliable and tamper-resistant referrer data. The API returns the referrer string, the timestamp of when the referrer was set (click time), and the timestamp of when the app began to install, enabling click-to-install time (CTIT) calculation.

Scope and Limitations

Install referrer is specific to Android and the Google Play Store. It does not apply to iOS, where attribution relies on SKAdNetwork, the App Tracking Transparency framework, and probabilistic modeling. On Android, installs from sources outside Google Play, such as direct APK downloads, do not generate a Play Store referrer.

Why it matters

Install referrer is the foundational attribution signal for Android app marketing. It enables marketers to connect app installs directly to the campaigns, networks, and creatives that drove them, making accurate return on ad spend (ROAS) calculation possible.

Without install referrer data, marketers have no reliable way to distinguish which channel delivered a given install, making budget allocation decisions speculative. With it, marketers can compare performance across channels, identify top-performing creatives, and reallocate spend toward sources that drive installs most efficiently.

Beyond install attribution, the referrer string enables downstream analysis. Marketers can segment cohorts by acquisition source and compare in-app behavior, lifetime value, and retention rates across channels. This reveals not just which channel drives volume but which drives quality users.

The CTIT data embedded in the referrer response also serves as a fraud detection signal. Unusually short or long click-to-install times can indicate click injection or click spam activity, helping MMPs and marketers identify and filter fraudulent installs before they distort campaign data.

For Airbridge users, install referrer data is automatically ingested and parsed, making it available alongside other attribution signals for unified cross-channel reporting.

How to set up install referrer tracking

Setting up install referrer tracking for Android requires integrating the Google Play Install Referrer API into your app and connecting it to your attribution workflow.

1. Integrate the Install Referrer Library

Add the Google Play Install Referrer library as a dependency in your app's build.gradle file. Google maintains this library and it provides a stable interface for querying the Play Store referrer data on first launch.

2. Integrate Your MMP SDK

Most MMPs, including Airbridge, handle referrer retrieval automatically when their SDK is integrated. The SDK queries the Install Referrer API on first open, parses the referrer string, and forwards the data to the attribution platform. Manual API calls are generally unnecessary when using an MMP SDK.

3. Structure Your Tracking Links Correctly

Ensure all ad and campaign links pointing to the Google Play Store include a properly encoded referrer parameter. Use consistent UTM parameter conventions across all channels so that reporting remains clean and comparable. Custom parameters for publisher IDs or creative IDs should also be included if granular sub-channel reporting is required.

4. Verify Referrer Data in Your Dashboard

After launching campaigns, verify that install referrer data is arriving correctly in your MMP dashboard. Check that utm_source, utm_campaign, and other parameters are populating as expected. Missing or malformed referrer strings indicate either a broken link setup or an integration issue.

5. Use CTIT Data for Fraud Detection

Review click-to-install time distributions in your attribution reports. Installs with extremely short CTIT values (under a few seconds) are strong indicators of click injection fraud. Configure your MMP's fraud filtering rules to flag or reject installs falling outside expected CTIT ranges.

6. Test Before Launch

Use test devices and internal tracking links to verify end-to-end referrer flow before launching paid campaigns. Confirm that the referrer string is retrieved correctly, that attribution matches the expected source, and that all custom parameters are preserved through the install process.

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