User.customdata
Opaque data the bidder previously stored in the exchange's cookie, handed back to that bidder in later requests. The bidder chooses the format, but the string must use cookie-safe characters.
Field facts
- Path
user.customdata- Object
- User
- Type
- string
- Requirement
- Optional
- Added
- OpenRTB 2.0
- Spec section
- 3.2.20
How it is used
It is a niche feature for bidders that want to keep a small value on the exchange side. Escape it properly as a JSON string. Like any cookie-derived value, it should follow the same consent gating as buyeruid.
Example
Where the field sits in a payload, with everything else left out:
{
"id": "req-1",
"user": {
"customdata": "v1.a7.fc3"
}
}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 |
Related fields
Other User fields
For a walkthrough of the whole object, read User identity and EIDs.