SDK

Attribution & click IDs

UTM strategy, click ID persistence, cross-domain _aid, short links, magic links.

AI brief: UTMs: URL-only per event (not persisted) so attribution models work. Click IDs (fbclid, gclid, etc.): persisted last-touch. Cross-domain: ?_aid and tracker.link(). Short URLs: ?_lid inbound_link_id in context.

Attribution data flows from the URL into each event context. The SDK deliberately avoids persisting UTMs in localStorage — doing so would poison multi-touch models. Click IDs for ad platforms are persisted with last-touch semantics.

UTM parameters

Param	Persisted?	Creates touchpoint
utm_source	No — URL only	Yes, per landing with UTMs
utm_medium	No	Yes
utm_campaign	No	Yes
utm_content	No	Yes
utm_term	No	Yes

Click IDs (CAPI-critical)

Param	Platform	Persistence
fbclid	Meta	Last-touch in localStorage
gclid	Google Ads	Last-touch
ttclid	TikTok	Last-touch
msclkid	Microsoft	Last-touch
li_fat_id	LinkedIn	Last-touch

cross-domain.ts

// Site A — marketing landing
const url = tracker.link('https://app.example.com/signup');
// → https://app.example.com/signup?_aid=anon_xyz

// Site B — product app (same or different init)
tracker.init({ endpoint: 'https://api.trackrift.com', publicId: 'YOUR_PUBLIC_ID' });
// bootstrap reads ?_aid= and adopts anonymous_id

Magic links (?_uid=)

Email campaigns can include ?_uid=<signed_token>. On load the SDK POSTs to /m to merge the anonymous journey with a known identity without a login form.

Internal navigation without UTMs

page_view on /pricing after landing on /?utm_source=google will NOT include UTMs — that is correct. Server touchpoints were recorded on the landing event.