# Property ID

> The identifier of the tracked website (property); it forms the prefix of every Click ID.

The Property ID identifies the **property** (website) being tracked. It is a structural identifier that describes your account setup rather than a single visitor.

## Why the Property ID matters

The Property ID forms the **prefix of every Click ID**, which is how AnyTrack knows which property a click belongs to. In server-side setups, the Click ID is the Property ID joined to the Client ID: `{propertyid}{cid}`.