Since an iPhone update in 2021, the numbers reported by Meta and Google have been drifting away from reality: real sales no longer show up in your dashboards. As a result, your campaigns learn from incomplete data, and you are steering half in the dark.
Why sales go missing.
To know that an ad led to a sale, Meta and Google rely on a small piece of code installed on your site: the pixel. It runs in the visitor's browser, and that is where things get complicated.
- On iPhone, most users decline tracking in apps like Facebook and Instagram.
- Safari, the browser on iPhone and Mac, quickly clears the small files (cookies) that let the pixel recognize a visitor from one visit to the next.
- Ad blockers often stop the pixel from loading at all.
- And some of your visitors simply decline cookies on your banner.
Taken one by one, these factors look marginal. Together, they open a gap between what the platforms see and what you actually sell.
Are you affected? The 5-minute test.
Over the last 30 days, compare the number of purchases received by Meta (in its Events Manager, under “Overview”, not in campaign results) with the number of orders recorded in your store. The difference is the sales the algorithm never sees, and therefore cannot learn from.
The pixel alone is no longer enough. It needs a server-side counterpart.
The fix, in one sentence.
Instead of letting the browser notify Meta and Google, at the risk of being blocked along the way, your site notifies them directly, the moment the order is confirmed.
The pixel stays in place; the server backs it up. Both send the same sale, with the same reference, and the platforms count it only once.
What it means for you.
- More accurate numbers: sales blocked by a browser or an ad blocker still come through.
- Campaigns that learn faster: Meta and Google show your ads to people who look like your buyers. The more sales they see, the better they find them.
- Fewer bad surprises: an iPhone update or a new ad blocker no longer sends your numbers tumbling overnight.
What it doesn't change.
Consent is still required. If a visitor declines cookies, nothing is sent, neither by the browser nor by the server. Server-side tracking recovers visitors who said yes but could not be measured for technical reasons, never those who said no.
Done right, or not at all.
Set up badly, server-side tracking can do more harm than good. Three points make all the difference:
- Never count the same sale twice: the pixel and the server must send the same order number.
- Send the right details (for example the buyer's email address, encrypted) so Meta and Google can link the sale to the right person.
- Watch that nothing breaks silently: a change to the checkout page can cut off the data without anyone noticing.
At Nelty, we set it up whenever the site allows it. It's also why we prefer to run advertising on sites we built: with access to the code, the setup is clean and can be monitored over time.