Site.id

The exchange's own identifier for the site. Recommended rather than required, and meaningful only within that exchange.

CurrentstringRecommendedSince 2.0

Field facts

Path: site.id
Object: Site
Type: string
Requirement: Recommended
Added: OpenRTB 2.0
Spec section: 3.2.13

How it is used

Bidders use it as a stable key for allow lists, reporting, and learned performance, because names and URLs change more often than IDs. Two exchanges selling the same site use different values, so match across exchanges on Site.domain.

Example

Where the field sits in a payload, with everything else left out:

{
  "id": "req-1",
  "site": {
    "id": "site-10482"
  }
}

Version history

Added in OpenRTB 2.0, and present in the latest snapshot. The table shows how each version's spec text types the field.

Versions	Type in the spec	Required	Deprecated
2.0 to 2.2	string	Recommended	No
2.3 to 2.3.1	string	Recommended	No
2.4	string	Recommended	No
2.5 to 2.6-202606	string	Recommended	No