EID.source

The canonical domain of the identity provider, such as "id-provider.example". It tells buyers which ID system the values in uids belong to.

CurrentstringOptionalSince 2.6-202204

Field facts

Path: user.eids.source
Object: EID
Type: string
Requirement: Optional
Added: OpenRTB 2.6-202204
Spec section: 3.2.27

How it is used

Use the domain the provider documents, lowercase, with no scheme or path; buyers match it as an exact string. The 2.6 table does not mark it required, but an EID without a source cannot be routed.

Example

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

{
  "id": "req-1",
  "user": {
    "eids": [
      {
        "source": "id-provider.example"
      }
    ]
  }
}

Common mistakes

Omitting source. RTBlint reports it, and buyers cannot tell which ID system the value belongs to.
Sending a full URL such as "https://id-provider.example/" instead of a bare domain, which breaks exact-match lookups.

Version history

Added in OpenRTB 2.6-202204, 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
2.6-202204	Added in the first 2.6 release, published without a structured text archive; the 2.6-202210 republication is the first tagged text.
2.6-202210 to 2.6-202606	string	No	No

Related fields

Other EID fields

For a walkthrough of the whole object, read User identity and EIDs.