Bid.burl

The billing notice URL, which the exchange calls when a winning bid becomes billable under its own policy, typically on delivery or view. Added in 2.5.

CurrentstringOptionalSince 2.5

Field facts

Path: seatbid.bid.burl
Object: Bid
Type: string
Requirement: Optional
Added: OpenRTB 2.5
Spec section: 4.2.3

How it is used

The exchange should fire it server-side, as close as possible to where it books revenue, to keep discrepancies small. For VAST, the IAB treats the VAST impression event as the billable signal, so an exchange following that policy fires burl at the same moment. Put ${AUCTION_PRICE} here if this notice drives your spend accounting.

Example

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

{
  "seatbid": [
    {
      "bid": [
        {
          "burl": "https://bill.dsp.example/b?imp=${AUCTION_IMP_ID}&price=${AUCTION_PRICE}"
        }
      ]
    }
  ]
}

Common mistakes

Counting both the billing notice and an impression pixel in the markup as billable events, which double-counts spend.
Leaving the price macro off both notice URLs (openrtb.bid.price_macro_missing).

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 to 2.6-202606	string	No	No

Related fields

Other Bid fields

For a walkthrough of the whole object, read Bid response anatomy.