Parallel tracking

With parallel tracking (the default for Google Ads), a click sends the visitor straight to your final URL. At the same time the browser requests your tracking template in the background. The visitor never waits for the tracker.

What happens on a click#

1. The visitor clicks the ad and Google opens the final URL with gclid (or gbraid / wbraid) appended.
2. In the background the browser requests the tracking template: https://track.example.com/c/KEY?gclid=…&url=https%3A%2F%2Fshop.example.com%2F.
3. The tracking domain records the click and answers with a single 302 to the url value. The browser follows it silently — that is expected; the page itself is already loading.

Because the visitor did not pass through the tracking domain, the landing page has the gclid but not our click ID.

Attributing on-site conversions#

Choose one of these:

• Landing-page SDK — add the SDK. It sees the gclid in the page URL, asks the tracking domain for the click recorded for that gclid and keeps its click ID. Conversions fired with ArcTrack.conversion(…) or links decorated with the click ID then attribute normally.
• Postback by gclid — store the gclid with the order and send it in the S2S postback instead of a click ID:

https://track.example.com/pb?gclid=GCLID&event=sale&amount=49.90&txid=ORDER-1001&token=TOKEN

The latest click in your workspace with that gclid is used.

• Offline conversion import — conversions recorded in ArcTrack are sent back to Google Ads through an offline conversion feed.

Timing#

The background request can arrive a moment after the landing page loads. The SDK waits for the click (up to five seconds) before it falls back to a stored click ID.

Checklist#

• Tracking template uses /c/ with url={lpurl} last.
• Every landing-page hostname is on the allowlist.
• The SDK is on the landing page, or the advertiser sends gclid in postbacks.