Benefits of server-side tracking: why your cookies disappear in Safari after one day

Server-side tracking no longer sends your measurement data straight from the browser to Google or Meta. It goes to a server on your own subdomain first. That sounds like a technical detail. In practice it decides whether an order is attributed to the ad that triggered it. The main reason is Safari.

The scenario: clicked on Monday, bought on Wednesday

On Monday evening a customer sees your ad on Instagram on her iPhone, taps it and lands in your shop. She looks at two products, adds one to the basket and closes the app. On Wednesday she types your address straight into Safari and places the order.

With classic tracking, this order is lost to your ad. The reason: when she clicked, the ad added an identifier to the address, fbclid for Meta, gclid for Google. Safari recognises such links. Cookies that a script on the landing page sets afterwards are deleted by Safari after just 24 hours. By Wednesday the cookie holding the campaign information is gone. The order shows up in your reports as a direct visit, and Meta concludes the ad achieved nothing.

What Safari does with cookies

Behind this is Intelligent Tracking Prevention, ITP for short, which Apple has tightened step by step over the years. Three rules matter for tracking:

• Cookies set via JavaScript in the browser expire in Safari after seven days at most, whatever expiry date the script sets.
• If someone arrives via a link with a click identifier from a site that Safari classifies as a tracker, this period shrinks to 24 hours.
• In private browsing, Safari even removes known click identifiers from the address.

A large share of your visitors use an iPhone, and on the iPhone other browsers also run on Safari’s engine. So the gap does not just affect a small group.

How server-side tracking solves this

With server-side tracking, the cookie is not set by a script in the browser but by your own server, under your domain. Safari’s short limits do not apply to such cookies, as long as the server properly belongs to your website. That is why the setup matters: since Safari 16.4, Apple also shortens cookies set by a subdomain whose server runs on a completely different IP address from your website. The subdomain and the hosting of the server container therefore have to fit together.

Set up correctly, your shop recognises the customer again on Wednesday. The order is attributed to Monday’s ad, and Meta learns from it.

The benefits at a glance

More complete measurement. Ad blockers block the known addresses of Google and Meta. When measurement runs through your own subdomain, considerably more events get through.

Returning customers recognised for longer. Server cookies survive Safari’s limits. For products people think about for a few days, that makes the difference between an attributed and a lost order.

Better data for your campaigns. Google Ads and Meta adjust bids based on the conversions they see. If purchases are missing, the algorithms bid on the wrong audiences. With more complete data, your budget goes to the ads that actually sell.

Control over your data. The server container is a switchboard. You decide which data goes to which service, shorten IP addresses or leave individual fields out entirely. That fits the principle of data minimisation better than a script that passes everything straight on.

Faster pages. Instead of several scripts from Google, Meta and other providers, the browser only loads a little code. The page gets faster, which visitors and Google both appreciate.

One source for several services. A purchase event from your shop goes to the server once and from there to Google Analytics 4, Google Ads and the Meta Conversions API. All systems work with the same figures.

What server-side tracking is not

Server-side tracking is not a way around the consent banner. Analytics and marketing usually still require consent, and the server container only passes on what has been consented to. Every setup therefore includes aligning it with your consent banner and Consent Mode. The server container also has a monthly fee depending on hosting and needs maintenance when Google or Meta change their interfaces.

Conclusion

If you advertise on Google or Meta, classic tracking loses a noticeable share of your conversions, especially from iPhone users. Server-side tracking closes this gap, gives your campaigns better data and puts you back in control of which data leaves your systems.

Want to implement this for your shop? We set up your server-side tracking at a fixed price, aligned with your consent banner and reconciled with your shop revenue.