Short answer: When your website sends visitors to an external platform like HealthEngine, Raisely or Big Red Sky to finish a booking, donation or job application, Google Ads, Meta and GA4 usually lose track of them. To fix it, carry the campaign data across the handover, set up cross-domain tracking where the platform allows it, and send confirmed conversions to your ad platforms from the server using tools like Meta's Conversions API and Google's offline conversion imports.

Why do conversions go missing on third-party platforms?

Your website and the external platform are two separate systems on two separate domains. When a visitor clicks "Book now", "Donate" or "Apply", the platform sees them as a new visitor. The click ID (gclid or fbclid), the cookies and the UTM campaign details that link them to your ad are often lost along the way.

The booking, donation or application still happens. Google Ads, Meta and GA4 just never hear about it.

Which platforms does this affect?

This affects any website where the final step happens off-site. Common examples in Australia include:

• Jobs and recruitment: Big Red Sky, PageUp, JobAdder, Workday, SmartRecruiters, Avature
• Donations and fundraising: Raisely, Funraisin, GiveNow, Blackbaud, Fundraise Up
• Health and allied health bookings: HealthEngine, HotDoc, Cliniko, Halaxy, Nookal
• Tours, venues and events: Rezdy, FareHarbor, Bookeo, ResDiary, Eventbrite, Humanitix
• Fitness, beauty and services: Mindbody, Timely, Fresha

What happens if you don't fix it?

• Reporting undercounts. Campaigns show clicks but few conversions, so they look like they're failing when they aren't.
• Ad algorithms optimise for the wrong thing. Meta and Google Ads bidding learns from the conversions it can see. If it only sees page views, it finds you more page viewers, not more bookings, donors or applicants.
• Budget goes to the wrong campaigns. You can't tell which channel drove the result, so spend decisions are guesswork.
• Audiences shrink. Retargeting and lookalike audiences built on completed conversions end up thin or empty.

How do you track conversions across two domains?

There's no single fix, because each platform allows different levels of access. These are the steps we follow:

1. Check what the platform supports. Find out whether it accepts your Google Tag Manager container, only a pixel or measurement ID, offers webhooks or an API, or allows no tracking at all.
2. Pass campaign data across. Add click IDs and UTM parameters to the outbound booking, donation or application link so they survive the handover.
3. Set up GA4 cross-domain tracking. If the platform allows your tags, configure GA4 so it sees one continuous journey instead of two separate visitors.
4. Use server-side tracking. Send confirmed conversions directly to Meta's Conversions API, Google Ads enhanced and offline conversions, and GA4's Measurement Protocol. This isn't affected by ad blockers, Safari's cookie limits or redirects.
5. Brief the platform vendor. Some fixes need a change on the vendor's side, such as a webhook or a confirmation-page tag. A clear technical brief gets this done faster.
6. Test with real transactions. Make a real booking, donation or application and confirm it appears correctly in each ad platform before you rely on the data.

What should you ask a platform before signing up?

• Can we add our own Google Tag Manager container, or only a pixel ID?
• Can URL parameters like gclid, fbclid and UTMs be passed through and stored with the booking?
• Do you offer webhooks or an API that sends confirmed transactions to us?
• Do you have a native integration with Meta's Conversions API or Google Ads?
• Is there a confirmation page on our domain, or does the journey end on yours?

If the vendor can't answer these, plan for a gap in your reporting.

Frequently asked questions

Does GA4 cross-domain tracking fix this on its own?

Only if the external platform lets you install your GA4 tag. Many booking and donation platforms don't, so server-side tracking is often needed as well.

Will the Meta pixel on my website track bookings made on HealthEngine or Rezdy?

Usually not. The pixel only fires on pages where it's installed. If the booking is completed on the vendor's domain, Meta won't see it unless the platform supports your pixel or sends data through the Conversions API.

Is server-side tracking compliant with Australian privacy law?

It can be, as long as data collection matches your privacy policy and consent settings. Server-side tracking gives you more control over what's sent, not less.

How long does it take to set up?

It depends on the platform. A platform that accepts GTM can be done in a few hours. One that needs an API or a vendor change can take a few weeks.

Need help connecting your website to your booking, donation or job platform?

Bang Digital is a Perth digital marketing agency specialising in GA4, Google Tag Manager and server-side tracking. If your website sends people elsewhere to apply, donate or book, we can audit what's being tracked, show you where the gaps are and fix them. Contact the Bang Digital team.