Property

A property is the container that holds your analytics data in GA4. The hierarchy goes account → property → data stream: an account is the top-level organisation, a property is one website or app's worth of data, and data streams feed events into it. Each property has its own reports, its own settings, and its own Measurement ID.

Why it matters

The property is the boundary of your data. Reports, audiences, key events, and retention settings all live at the property level, and data does not cross between properties. Decide what belongs in one property and what should be separate, and you've made the most consequential structural choice in your GA4 setup — one that's painful to undo later.

A concrete example

A consultant with one website and one booking subdomain usually wants a single property with two data streams, so the whole visitor journey lives in one place. A franchise running ten independent regional sites might want ten properties, one per site, so each owner sees only their own numbers. The right structure depends on whether you want the data combined or kept apart.

The common misreading

The frequent mistake is confusing a property with an account, or assuming you can merge two properties later. You can't merge them — historical data stays where it was collected. People who split one website across two properties by accident end up with two half-pictures and no way to stitch them together retroactively. Settle your property structure early, and check your reporting identity while you're there.