Site.domain

The domain of the site, written as a bare hostname such as news.example.com with no scheme, path, or port. Buyers use it for targeting, block lists, and ads.txt lookups.

CurrentstringOptionalSince 2.0

Field facts

Path: site.domain
Object: Site
Type: string
Requirement: Optional
Added: OpenRTB 2.0
Spec section: 3.2.13

How it is used

Keep Site.domain consistent with Site.page: it should be the host of the page URL or its parent domain. Buyers usually reduce it to the registrable domain before matching ads.txt, so a leading www rarely matters, but a domain that does not match the page looks like spoofed supply.

Example

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

{
  "id": "req-1",
  "site": {
    "domain": "news.example.com"
  }
}

Common mistakes

Sending a full URL such as https://news.example.com/ in domain. The validator warns that the value contains URL syntax, and ads.txt matching can fail.
Sending the domain of the ad server or exchange instead of the publisher, usually because the request was built inside an iframe.

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	No	No
2.3 to 2.3.1	string	No	No
2.4	string	No	No
2.5 to 2.6-202606	string	No	No