Sending billable event notifications (burl) to Index through client-side beaconing

Media Owners
Last Updated: February 17, 2026•

You can use client-side beaconing to send billing notifications (burl) to Index Exchange (Index). When you use client-side beaconing, the burl is sent from your site or app code, typically from an ads SDK, when a billable event occurs. To use burl with Index, your SDK or server must support HTTP 302 redirects. To enable burl with Index, contact your Index Representative.

In the mobile app banner example below, the following steps describe how burl works in an OpenRTB interaction between a publisher, Index, and a DSP.

Image showing the steps described below

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The ad SDK generates an ad request and sends it to your ad server. The ad server then makes a bid request to Index.

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Index sends a bid request to the DSP.

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The DSP sends a bid response to Index that includes the following fields in the bid response object:

  • adm: The creative 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 Index receives the burl within the TTL, Index sends the DSP's burl, regardless of the DSP's expiry time. For more information about TTL, see How Index counts impressions.

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Index captures the DSP's burl.

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Index sends a bid response to your ad server that includes the following fields in the bid response object:

  • adm: The creative markup (HTML or VAST), including the Index ad load notice.
  • burl: The Index billing notice which is different from the DSP's billing notice burl (stored in step 4). This notifies Index that the Media Owner considers the impression billable.

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Your ad server conducts the final auction and if the bid wins the auction, the ad displays to the user.

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The ad is downloaded which causes the device to send the Index ad load notice, which was inserted in the ad markup (adm). This notifies Index that the ad has begun to render.

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The device sends the Index burl when a billable event occurs. For example, for banners in mobile app, at least one pixel of the banner is painted in the viewport of the user's device.

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Index retrieves the DSP burl (stored in step 4) and returns it to your SDK as a HTTP 302 redirect.

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Your SDK follows the HTTP 302 redirect to send the DSP burl.