Apple’s iOS 14.5 update shipped in April 2021 and made tracking opt-in through App Tracking Transparency. At the time, in-app advertising was estimated as a $314.5 billion industry growing around 10% a year, and almost all of its measurement ran on device IDs. Five years on, the dust has settled, and the stack that works on Snap looks quite different.
What iOS 14.5 broke
Before the update, advertisers relied on SDKs and mobile measurement partners (MMPs) to send conversion data back to ad platforms, keyed to device IDs. When Apple made tracking consent mandatory, most users declined, and conversion events started arriving with no device ID attached.
That missing link had predictable effects: ROAS reporting dropped, remarketing audiences shrank, and campaign optimisation starved. The problem was never that conversions stopped happening. Platforms simply stopped being able to see them.
SKAdNetwork and the aggregate era
MMPs adapted by building on SKAdNetwork, Apple’s privacy-preserving attribution framework, which reports campaign results directly from iOS devices without exposing user-level data. Apple has iterated on the framework since, but the model is unchanged: attribution arrives aggregated, delayed, and stripped of detail.
That keeps install reporting alive. It also leaves marketers with a black box. Aggregate insights can be speculative on app ROAS, and there is limited visibility into which campaigns actually drive value. Snap’s answer was to add a second signal path alongside MMP reporting rather than trying to rebuild the old one.
Snap App CAPI
Snap’s App Conversions API, also called Advanced Conversions, is a secure server-to-server connection that transmits app events to Snap using hashed first-party data. Where SKAdNetwork answers “which campaign drove installs”, App CAPI carries the post-install events that matter commercially: registrations, purchases, subscription starts, matched on consented identifiers rather than device IDs.
Snap positions it as a complement to MMPs, and in practice that is how it runs. The MMP or your backend remains the system of record for app events; App CAPI is the delivery path that gets those events to Snap with enough match signal for the auction to optimise on.
Where app measurement stands in 2026
The post-ATT stack has stabilised into two layers. Aggregate attribution frameworks handle iOS install reporting within Apple’s privacy rules. Server-side conversion delivery, fed from your MMP or backend, gives Snap the event-level signal that ranking and bidding need. App campaigns that run both layers are measuring; campaigns still waiting for device IDs to come back are not.
Getting there is an integration decision. Your engineering team can build the connection directly against Snap’s spec, or use a turn-key setup: through Datahash, a Snap App CAPI integration takes one to two days, with identifiers hashed before anything leaves your systems.
Explore Snap App CAPI to see what a server-side app signal setup looks like for your stack.