Outbound click flag dimension
Outbound is the boolean dimension on GA4's click event that records whether the clicked link led to a different domain. Enhanced measurement only auto-fires the click event for outbound links, so in practice the auto-captured values are true; the field exists so manually-sent click events can also be flagged. Understanding it clarifies why same-domain clicks never appear in outbound-click reports by default.
What this means
GA4's click event carries an 'outbound' boolean parameter that is true when the destination domain differs from your site. Enhanced measurement only fires this event automatically for outbound links, so the auto-collected data is overwhelmingly outbound=true.
The dimension is most useful as a filter to ensure your click reports represent genuine site exits rather than custom events you mislabelled.
Why internal clicks are absent
Because automatic click tracking is scoped to outbound links, clicks within your own domain are recorded as page_view navigations, not click events, and so have no outbound flag. To analyse internal link clicks you send your own events.
Cross-domain configuration also moves the boundary: domains you mark as yours stop being outbound and drop out of these reports.
- Boolean on the GA4 click event
- Auto-captured clicks are outbound=true
- Internal clicks are page_views, not click events
How it appears in analytics and logs
An outbound value of true marks a link that left your domain. If you see internal clicks here, they were sent by custom events that set outbound deliberately, not by enhanced measurement.
Diagnostic use case
Use the outbound flag to confirm that captured click events represent links leaving your site, and to explain why internal clicks are absent from these reports.
What WebmasterID can help detect
WebmasterID can distinguish first-party internal navigation from outbound clicks at the event layer, without third-party tracking on the destination.
Common mistakes
- Expecting internal clicks to carry an outbound flag.
- Reading outbound=true as proof a link is genuinely external after cross-domain changes.
- Forgetting custom click events can set outbound to any value.
Privacy and accuracy notes
The outbound flag records link behaviour, not a person. WebmasterID records whether a click left your site as first-party context, without profiling the visitor.
Related pages
- Link domain dimension
Link domain is the dimension that records the destination host of a clicked outbound link — the domain portion of link_url. GA4 enhanced measurement sets it on the click event so you can group outbound traffic by where it goes (a partner, a payment provider, a social network) without parsing full URLs. What counts as outbound, and therefore what appears here, depends on your cross-domain measurement configuration.
- Link URL dimension: where outbound clicks go
Link URL is the dimension that records the destination of a clicked link. In GA4 it is populated by the click event from enhanced measurement, which fires on outbound links and carries link_url, link_domain, and link_text. It answers 'where did people leave to?', but its automatic scope is limited to links leaving your domain — internal and same-domain clicks need separate handling.
- The click event and outbound clicks
A click event records that a visitor activated a link or element. The most common analytics use is the outbound click — a click on a link leaving your domain — which a normal page_view can never capture because the destination is another site. This page covers what to record on a click, how outbound detection works, and which properties stay privacy-safe.
- CTA tracking
Separate outbound exits from internal clicks.
Sources and verification notes
- Google Analytics Help — [GA4] Enhanced measurement eventsDocuments the click event and its outbound parameter.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.