---
title: "How Sealmetrics Reduces AdBlocker Data Loss"
description: "How 1st-party tracking on your own subdomain keeps Sealmetrics off the third-party block lists AdBlockers use, and why it reduces rather than eliminates ad-blocker loss."
canonical_url: "https://docs.sealmetrics.com/security-privacy/adblocker-bypass"
lang: "en"
date_generated: "2026-10-08T17:47:47.862Z"
source_hash: "551abe5c6ba6f76ae82535e9dd2fda818aaed1ff8784a3f610141d51cbf6ca66"
content_type: "trust-and-legal"
owner: "legal"
llm_priority: "critical"
source_file: "security-privacy/adblocker-bypass.mdx"
publisher: "Sealmetrics"
---

# How Sealmetrics Reduces AdBlocker Data Loss

Canonical page: https://docs.sealmetrics.com/security-privacy/adblocker-bypass

## 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? {#how-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](/compliance)).
- **Resilient** — [Safari ITP](https://webkit.org/blog/7675/intelligent-tracking-prevention/), [Firefox ETP](https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop) and Chrome's [Privacy Sandbox](https://privacysandbox.com/) 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? {#how-to-configure-1st-party-tracking}

See the [First-party tracker guide](/implementation/tracker/first-party): 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.

**Note:**
- 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.

## Related documentation

- [1st Party Tracker](/implementation/tracker/first-party) — the first-party architecture that avoids ad-blocker filters
- [First Party Tracker](/implementation/tracker/first-party) — configure the first-party subdomain
- [Installation](/implementation/tracker/installation) — install and point a subdomain at the pixel
- [Bot Detection & Traffic Quality](/security-privacy/bot-detection) — how captured traffic is kept clean of bots
- [Frequently Asked Questions](/faq/privacy-security) — common privacy and tracking questions