I’m trying to track app install attribution for iOS using Google Analytics + Firebase — specifically to attribute installs back to the original traffic source (e.g., Google Ads, Meta, or other ad networks, owned web site, sns).

However, after reviewing both Firebase and GA documentation, I haven’t found a clear or official way to achieve this. Unlike Android, iOS doesn’t support install referrer tracking, so it’s technically difficult to understand which ad or traffic source led to an install when the user flows through the App Store.

From what I understand, this attribution gap stems from iOS limitations, particularly:

• No access to install referrer (like on Android)

• SKAdNetwork data in Firebase is available only for Google Ads

• UTM parameters aren’t preserved through App Store redirect

Given these constraints, I’m considering proposing a Mobile Measurement Partner (MMP) solution internally — like AppsFlyer — since MMPs seem to have:

• Probabilistic modeling

• Integration with non-Google ad networks

• Device ID matching (where allowed)

• Broad SKAdNetwork support

But I’m struggling to make the case without solid confirmation that GA + Firebase alone can’t deliver reliable iOS install attribution across multiple ad platforms.

If anyone has implemented this (or tried), I’d love to hear:

• Can GA + Firebase truly support iOS install attribution outside of Google Ads?

• Or is an MMP the only viable path for reliable, cross-channel iOS attribution?

Thanks in advance!