Voluum → Google Ads Postback
A postback from Voluum to Google Ads doesn't work like a real-time server CAPI event — it's an offline conversion import keyed to gclid instead. Here's how to capture gclid on the click in Voluum, set up the upload into a Google Ads conversion action, and avoid creating a duplicate conversion row.
Offline conversions instead of server-side events
Unlike Facebook and TikTok, where a postback turns into an API event almost instantly, Google Ads works by accumulating confirmed conversions and uploading them in periodic batches. Each row in that upload is tied to the gclid click identifier rather than pixel cookies.
Capturing gclid in Voluum
Google Ads appends a gclid parameter to the link on an ad click, and Voluum needs to store it alongside its own Click ID on that first hit. If the PWA page or a wrapper domain trims the query string on a redirect, gclid gets lost, and there's nothing left to import the conversion against in Google Ads.
Setting up the conversion action and the Voluum upload
In Google Ads, create a conversion action with the source set to Import → Clicks, then connect the Google Ads integration in Voluum and specify which conversion statuses map to that action, including value and currency. The conversion action's name has to match exactly what's set in Voluum's mapping, or the upload won't attach in the Google Ads interface.
No event_id: avoiding duplicates in the upload
Google Ads has no shared event_id deduplication — a conversion row's uniqueness rests on the combination of gclid, conversion action and conversion time. That means Voluum should upload a conversion exactly once, right when the status flips to confirmed, not on every repeat postback from the network. Google Ads has a separate adjustments mechanism for correcting an already-uploaded conversion's value, which doesn't create a new row.
FAQ
- What happens if gclid gets lost somewhere on the way to Voluum?
- There's nothing to match the conversion against in Google Ads, so it simply won't import — worth checking that the PWA page and any redirects aren't trimming the query string.
- How often should offline conversions get uploaded from Voluum to Google Ads?
- Uploading regularly, within a day of the status being confirmed, works fine — just make sure it falls inside the conversion window set on the Google Ads conversion action itself.
- Can the same conversion be re-uploaded if it didn't attach the first time?
- Check the upload status in the Google Ads interface first — re-uploading the same gclid, action and time combination risks creating a duplicate row instead of fixing the existing one.
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