v130 · miscellaneous

Attribution Reporting API Feature (Attribution Scopes)

We are landing the following changes to the Attribution Reporting API focused on: * providing more control over the attribution filtering

concepts

  1. Attribution Scopes simulator

    Pick scopes on a registered source, pick the scope on a conversion trigger, and see whether the browser would attribute the conversion. Client-side simulation of the new attribution_scopes field.

  2. Cross-campaign confusion

    The original ad-tech complaint that motivated scopes: multiple campaigns sharing the same conversion destination. Walks through a user journey and contrasts pre-Chrome 130 attribution (wrong campaign credited) with scope-aware attribution.

  3. Registration header builder

    Hands-on builder for the new attribution_scopes field on the Attribution-Reporting-Register-Source response. Live spec validation covers the 20-effective-scope ceiling, 50-character source scopes, scope_limit and max_event_states bounds, duplicate collapse, and multi-scope trigger-match preview.

  4. Scope event-state visualizer

    Add scopes to a source (up to the scope_limit), fire conversion triggers with one scope, multiple scopes, or no scope, and watch which source scopes observe distinct event states. Triggers outside the source's scope set are filtered; exceeding max_event_states is shown as a configuration warning, not a trigger quota.

  5. Too-aggressive scoping

    Scope sources narrowly, then fire an explicit trigger scope that is similar but not identical. Chrome 130 filters out every candidate and reports nothing, while an exact match attributes normally and an omitted trigger attribution_scopes field remains broadly eligible.

  6. Scope truncation demo

    When attribution_scopes.limit is smaller than values.length, the browser silently truncates the list to the first limit entries at registration time. Drag the limit slider, watch chips turn red as they get dropped, then test a trigger scope to see exactly how truncation changes attribution matching.

why it shipped

This change is based on ad-tech feedback and the need for more fine grained filtering controls before the attribution process takes place.

references