Full Answer

Ad blockers work by intercepting outbound network requests from the browser — they target known tracking domains, pixel scripts, and tag manager containers. Server-side tracking sidesteps this entirely by collecting the event at the server level (a WooCommerce hook, a form submission handler, a page-load trigger on the backend) and forwarding it to Google Ads, Meta CAPI, or GA4 via server-to-server API calls. The browser never makes the request, so the blocker has nothing to block.

The 95% bypass rate reflects the reality that most ad blockers are browser extensions or built-in browser filters. They cannot see or intercept HTTP requests that originate from your web server. The remaining 5% accounts for edge cases: DNS-level blockers like Pi-hole that block the tracking domain at the network layer, visitors with JavaScript disabled entirely, and aggressive privacy configurations that prevent even first-party cookie setting.

When both client-side and server-side run in parallel, ad platforms use event IDs to deduplicate. If the browser pixel fires and the server event arrives for the same conversion, the platform counts it once. If the pixel is blocked, the server event fills the gap. This hybrid approach is why the [recovery figure sits between 20 and 40%](https://seresa.io/blog/data-loss/912-million-ad-blockers-are-hiding-a-third-of-your-woocommerce-traffic) — it represents the net new conversions your ad platforms see that they previously missed.