Since the Digital Markets Act forced Apple to allow third-party app marketplaces on iOS within the EU, several alternative stores have built a real foothold there, some undercutting Apple’s standard commission by a wide margin. For users, it’s more choice about where an app comes from. For anyone running attribution, it’s a second install path that most existing measurement wasn’t built to see. SKAdNetwork and Apple’s AdServices attribution framework are scoped to the App Store; an install sourced through an EU alternative marketplace doesn’t automatically flow through the same attribution signal, even though Apple has expanded developer-facing APIs and analytics access as part of DMA compliance.
The risk isn’t that alternative-store installs are untracked in some abstract sense — it’s that they’re invisible in exactly the reports growth teams already trust. A campaign dashboard built around SKAdNetwork postbacks will show a clean, complete-looking funnel for App Store installs while quietly missing every install that came in through an EU marketplace, with no error, no gap flagged, nothing to indicate the data is partial. Spend allocated against that dashboard ends up optimised for the channel that happens to still be measurable, not the channel that’s actually performing — and as alternative-store share grows in the EU, that blind spot gets larger every quarter without changing how the dashboard looks.
Data Points to Track
- Install source per session, distinguishing App Store, each EU alternative marketplace your app is distributed through, and direct/sideloaded installs, rather than assuming “iOS install” means “App Store install”
- Attribution completeness rate by install source, measuring what share of installs from each channel actually carry a usable attribution signal, since App Store and alternative-store installs won’t have equivalent coverage
- EU alternative-store install share over time, tracked as its own trend line, since a channel that’s currently a rounding error can become material within a few quarters as marketplaces mature
- Campaign performance recalculated with alternative-store installs excluded versus included, run as a standing comparison, to quantify exactly how much a blind spot is distorting reported channel performance
- Cross-store user overlap, where technically knowable, to catch cases where the same user is being counted as a fresh acquisition across more than one store’s reporting
Setup Steps
- Capture install source as an explicit, first-class property on first open, using whatever signal each distribution channel provides, instead of defaulting every iOS install into a single App Store bucket.
- Build a parallel attribution path for each EU alternative marketplace your app ships on, since SKAdNetwork and AdServices won’t cover installs that didn’t originate from the App Store.
- Add an attribution-completeness check to your existing acquisition dashboard — a visible “% of installs with no attribution signal” figure, rather than letting unattributed installs disappear into an “organic” bucket by default.
- Re-run recent campaign performance reports with alternative-store installs modelled in, even roughly, to see whether current budget allocation would change if the blind spot were closed.
- Review this quarterly rather than once — DMA-driven marketplace adoption in the EU is still moving, and an attribution setup that was adequate at 2% alternative-store share won’t stay adequate as that share grows.
Actionable Insights
If attribution completeness is meaningfully lower for EU traffic than for the rest of your iOS install base, that gap is very likely alternative-store installs falling outside SKAdNetwork coverage — the fix is building a source-specific attribution path for those marketplaces, not chasing a data-quality bug in your existing pipeline. A widening gap between “campaign performance as reported” and “campaign performance with alternative-store installs modelled in” is a signal that current budget allocation is increasingly wrong for the EU specifically, even if the rest of the world looks fine. And a growing EU alternative-store install share with a flat or shrinking App Store share in the same region is expected as the market matures under DMA — treat it as a channel shift to build attribution for, not as an unexplained drop in App Store performance to investigate.
Related Resources
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