Full Answer

The tracking gap is specific to attribution, not event capture. TikTok Pixel can still fire browser events on iOS Safari — pageviews, add-to-cart actions, and purchases all trigger normally if the user has not blocked tracking scripts. The problem is that TikTok cannot connect those browser events to the specific ad the user saw in the TikTok app.

Before ATT, TikTok used Apple's IDFA (Identifier for Advertisers) to link a user who viewed an ad in the TikTok app to the same user who later purchased on a website. ATT removed this link for opted-out users. TikTok's SKAdNetwork integration provides limited, delayed, aggregate conversion data as a fallback, but it does not support real-time optimization or individual-level attribution.

The scale of the gap is significant for WooCommerce stores advertising on TikTok. If 50% of your traffic is mobile and 60% of mobile traffic is iOS, roughly 30% of your total audience is invisible to TikTok's attribution model. Ad campaign performance appears worse than reality because conversions from opted-out users are not counted.

TikTok Events API solves the attribution problem by matching users through hashed first-party data rather than device identifiers. When a customer completes a purchase, your server sends the order event to TikTok with SHA256-hashed email or phone number. TikTok matches this against the hashed identifier of users who interacted with your ads. This server-to-server matching does not depend on browser state, device identifiers, or ATT consent.