v150 · Web APIs · Privacy

Event Source Comparison

The Attribution Reporting API is being removed following the Privacy Sandbox wind-down. This page compares the event-level source registration flow (old API) against the recommended replacement — server-side conversion tracking with aggregate reporting — and probes which API surfaces are still available in the current browser.

Old: Attribution Reporting API (removing)
1
Ad click triggers attributionsrc request to report endpoint
2
Server responds with Attribution-Reporting-Register-Source header
3
Browser stores source in OS-level storage; on conversion, fires Attribution-Reporting-Register-Trigger
4
Browser sends aggregatable report to /.well-known/attribution-reporting/report-event-attribution
5
Removed in Chrome 150 — attributionsrc, Attribution-Reporting-* headers no longer processed
Replacement: Server-side + Privacy-preserving
1
Ad click fires a POST to your ad server with a click identifier
2
Click ID stored in a partitioned, first-party cookie or URL parameter
3
On conversion page, server reads the click ID and records the match server-side — no browser APIs required
4
Reporting via Aggregation API, FLEDGE/PA, or aggregate logs — without cross-site tracking
5
Works in all browsers; no dependency on Privacy Sandbox APIs that require origin trials
API surface availability probe
API surface
Chrome 150+
Status
attributionsrc attribute
removed
—
Attribution-Reporting-Register-Source header processing
removed
—
document.featurePolicy.allowsFeature('attribution-reporting')
removed
—
navigator.cookieEnabled
still available
Click "Run probe" to detect which Attribution Reporting API surfaces are available in this browser.
/* Old: attributionsrc on <a> or <img> — removed */ <a href="/landing" attributionsrc="https://ad.example/register-source">Click ad</a> /* Replacement: server-side click tracking */ <a href="/landing?click_id=abc123" onclick="recordClick('abc123')">Click ad</a> // Server records: click_id → conversion on server side // No browser-level attribution storage needed

see also

implementation reference

Need the exact API surface, compatibility boundaries, errors, lifecycle, and source links? Read the matching gendn reference ↗