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How Sealmetrics Reduces AdBlocker Data Loss

Why first-party delivery matters​

Most analytics platforms rely on third-party tracking domains, which are automatically flagged and blocked by AdBlockers. With 1st-party tracking on a subdomain of your own site, Sealmetrics is not on those lists, so far fewer visits are lost to ad blockers. No analytics tool is unblockable: a user or list maintainer can still add a custom rule.

How do AdBlockers work?​

AdBlockers typically block requests to well-known tracking domains such as:

  • google-analytics.com
  • facebook.net
  • doubleclick.net

When a pixel or script loads from a recognized third-party tracker, the AdBlocker intercepts and blocks it automatically.

This is one of the reasons traditional analytics lose data — alongside consent rejection.

Why Sealmetrics is rarely blocked​

Sealmetrics can use 1st-party tracking​

Instead of loading the pixel from a third-party domain, Sealmetrics works through your own domain, for example:

https://analytics.yourdomain.com/t.js

Because the request is served from a subdomain of your own site, it does not match the third-party tracking domains that AdBlockers such as uBlock Origin, AdBlock Plus or Brave Shields block by default, and Safari ITP's third-party cookie limits do not apply to it. A custom filter rule written against your subdomain can still block it.

Why does first-party tracking matter?​

  • Less data loss from ad-blocking users, whose share varies widely by audience and is highest among technical readers.
  • Accurate attribution — cookieless, server-side attribution works without cookies or third-party domains.
  • Designed for GDPR — first-party collection of minimal, pseudonymised data that becomes unrecoverable daily; our self-assessment is that it needs no consent banner (see Compliance).
  • Resilient — Safari ITP, Firefox ETP and Chrome's Privacy Sandbox target cross-site tracking, not first-party requests, so first-party delivery is not what those mechanisms are built to block.

How do I configure 1st-party tracking?​

See the First-party tracker guide: create the subdomain shown in the dashboard with a DNS A record, and the Sealmetrics team completes the server side.

Once configured, Sealmetrics can also measure visitors whose blockers work from lists of known third-party tracking domains, because the tracker is served from your own domain. A filter rule written against your subdomain can still block it.

In short
  • AdBlockers block requests to known third-party tracking domains (google-analytics.com, facebook.net, doubleclick.net); a Sealmetrics pixel served from a subdomain of your own site does not match those lists, which reduces (not eliminates) ad-blocker loss.
  • The share of ad-blocking users varies by audience; it comes on top of what consent rejection costs traditional analytics.
  • Set up 1st-party tracking with a DNS A record for the subdomain shown in the dashboard — see the First-party tracker guide.
Written and maintained by the Sealmetrics Team