Billing notifications

DSPs
Last Updated: April 30, 2026•

DSPs can use the OpenRTBClosed An open industry standard for communication between buyers and sellers of online advertising in real-time bidding auctions. It's published by the IAB.burl (billing notify URL) field in bid responses to request billing notifications and reduce reporting discrepancies. Index Exchange (Index) supports the industry standard method of impression measurement in mobile app by using the IABClosed Interactive Advertising Bureau (IAB). An advertising business organization that develops industry standards, conducts research, and provides legal support for the online advertising industry.'s Open Measurement Interface Definition (OMID) with our Media Owners. For more information about OMID, see Measuring impressions with OMID.

The following steps describe how burl works with OMID in an OpenRTBinteraction between a Media Owner, Index, and a DSPClosed Demand-Side Platform (DSP). A software platform that automates bidding decisions in real-time and efficiently connects buyers and audiences through an ad exchange or SSP. Also known as a buy-side platform..

Image showing how burl works with OMID as described in the steps below

How it works

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The ad SDK generates an ad request and sends it to the Media Owner's ad serverClosed A platform that manages, stores, and delivers advertisements to a publisher's site.. The Media Owner's ad server makes a request to Index.

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Index sends a bid requestClosed An OpenRTB request that is sent from a supply-side platform (SSP) or ad exchange to the DSP requesting a bid response for potential impressions. A bid request contains information about the impression that allows the DSP to decide whether to bid on the impression. to the DSP.

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The DSP sends a bid responseClosed An OpenRTB response that is sent by the DSP in response to the SSP's or ad exchange's bid request. It is an event directed back to the seller expressing a valuation for the request and conditions of sale. to Index that includes the following fields in the bid response object:

  • adm: The ad markup to render on the user's device.

  • burl: The DSP billing notice URL, to be sent when the impression becomes billable.

Note: Index holds the auction data related to burls for three hours. This is referred to as the impression time to live (TTL). If received within the TTL, Index will send the DSP's burl, regardless of that DSP's expiry time. For more information about TTL, see How Index counts impressions.

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Index injects our OMID script and the DSP burl as an attribute into the adm field of the bid response object.

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Index sends a bid response to the Media Owner with the following in the adm field: The ad markup (VASTClosed Video ad-serving template (VAST). A communication standard between ad servers and video players in XML-format that describes the video player's expected behavior. or HTML), that includes the IndexOMID script and the DSP burl.

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The Media Owner's ad server conducts the final auction and if the bid wins the auction, the ad displays to the user.

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When at least one pixel of the ad enters the viewport of the device, Index's OMID script determines that a billable event has occurred and fires both the Index impression notification and the DSP burl simultaneously.