User.id
The exchange's own ID for the user, normally the ID from the exchange's cookie unless buyer and seller agreed otherwise. It may rotate under privacy policies but should last long enough for frequency capping.
Field facts
- Path
user.id- Object
- User
- Type
- string
- Requirement
- Optional
- Added
- OpenRTB 2.0
- Spec section
- 3.2.20
How it is used
A buyer can use id only if it keeps its own match table keyed on the exchange's IDs; otherwise buyeruid is the field to read. Through 2.5 the spec recommended at least one of id or buyeruid. Never put raw personal data here: RTBlint flags email-shaped values.
Example
Where the field sits in a payload, with everything else left out:
{
"id": "req-1",
"user": {
"id": "exch-u-0000example"
}
}Common mistakes
- Putting an email address or other raw personal identifier in
id. - Generating a fresh ID on every request, which makes frequency capping impossible.
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 | Recommended | No |
| 2.4 | string | Recommended | No |
| 2.5 | string | Recommended | No |
| 2.6-202210 to 2.6-202606 | string | No | No |
Related fields
Other User fields
For a walkthrough of the whole object, read User identity and EIDs.