Source.fd

Says which party makes the final decision on the impression sale: 0 means the exchange itself, 1 means an upstream source such as a header bidding wrapper or publisher ad server. Added in 2.5 and recommended.

Currentinteger, recommendedOptionalSince 2.5

Field facts

Path: source.fd
Object: Source
Type: integer, recommended
Requirement: Optional
Added: OpenRTB 2.5
Spec section: 3.2.2

How it is used

When fd is 1, winning the exchange's auction only earns a place in a later decision, so buyers should expect some win notices that never become rendered or billed impressions. Pricing models often treat these requests as their own segment, because the upstream decision logic is not visible in the request.

Allowed values

0, 1.

Example

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

{
  "id": "req-1",
  "source": {
    "fd": 1
  }
}

Common mistakes

Hard-coding 0 on traffic that reaches the exchange through a header bidding wrapper hides the fact that the bid can still lose upstream.
Sending true or false instead of 1 or 0 is a type mismatch: the field is an integer in JSON.

Version history

Added in OpenRTB 2.5, 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
2.5	Integer	Recommended	No
2.6-202210 to 2.6-202606	integer, recommended	No	No

Related fields

Other Source fields

For a walkthrough of the whole object, read Supply chain (schain).