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Bidding Optimizations

Demand Partners

If you are setting up a new integration with OpenX Ad Exchange, or if you want to improve bidding efficiency for an existing integration, consider using some optimization methods. Contact your Platform Development Manager (PDM) for guidance or to enable any of the features included in this section.


Compressing Bid Requests

OpenX supports bid request and response compression via GZIP to reduce network bandwidth usage for demand partners. Partners who have enabled this feature have seen a 30-40% reduction in bandwidth utilization. To enable this feature or for more information, please contact your Platform Development Manager.


Compression can also result in increased CPU processing.

Receiving and Accepting Compressed Bid Requests

By default, as a demand partner, you receive non-compressed traffic. To receive compressed bid requests, please contact your Platform Development Manager. Once enabled, this change applies to all traffic OpenX sends you.

Compressed requests contain an HTTP header of:

Content-Encoding: gzip

Once this setting is enabled, monitor your systems to confirm that they are properly ingesting and decompressing requests and that bidding/spend behavior is not impacted.

Sending Compressed Bid Responses

You can respond to any OpenRTB bid request with either a non-compressed response or a compressed response. OpenX sends the Accept-Encoding: gzip HTTP header to indicate that it accepts compressed bid responses for all OpenRTB bid requests.

Adjust your bidder’s HTTP configuration to ingest this header and respond accordingly:

Accept-Encoding: gzip

When sending compressed responses, include the HTTP header below to indicate that it is compressed:

Content-Encoding: gzip

Receiving Loss Notifications

OpenX supports sending real-time loss notifications to demand partners via the lurl implementation introduced in the IAB’s OpenRTB 2.5 specification. To enable this feature or receive more information, please contact your platform development manager.


OpenX does not support secure lurl endpoints.

lurl Field in Bid Object

The lurl is the loss notice URL that is called by OpenX when a bid is known to have lost the auction. This value can be submitted by the demand partner as a field in the bid object of a bid response.

The OpenRTB substitution macro ${AUCTION_LOSS} may be included. For example, if the lurl was:${AUCTION_ID}&bid=920314&loss=${AUCTION_LOSS}

then the expansion might be:

where the code 102 means “Lost to Higher Bid” per the Loss Reason Codes table below.

The lurl submitted by a demand partner must be 500 characters or less. Submitted lurl values that exceed this limit with automatically be discarded.

Loss Reason Codes

The following table lists the codes and corresponding reasons for OpenX to inform a demand partner why they did not win an impression for a submitted bid.


The following is subject to regular updates. We strongly recommend regularly checking this table for new OpenX-specific loss codes/reasons (≥ 1000).

1Internal Error
2Impression Opportunity Expired
3Invalid Bid Response
4Invalid Deal ID
5Invalid Auction ID
6Invalid (malformed) Advertiser Domain
7Missing Markup
8Missing Creative ID
9Missing Bid Price
10Missing Minimum Creative Approval Data
100Bid was Below Auction Floor
101Bid was Below Deal Floor
102Lost to Higher Bid
103Lost to a Bid for a PMP Deal
104Buyer Seat Blocked
200Creative Filtered - General; reason unknown
201Creative Filtered - Pending processing by Exchange
202Creative Filtered - Disapproved by Exchange
203Creative Filtered - Size Not Allowed
204Creative Filtered - Incorrect Creative Format
205Creative Filtered - Advertiser Exclusions
206Creative Filtered – App Bundle Exclusions
207Creative Filtered – Not Secure
208Creative Filtered - Language Exclusions
209Creative Filtered - Category Exclusions
210Creative Filtered - Creative Attribute Exclusions
211Creative Filtered - Ad Type Exclusions
212Creative Filtered - Animation Too Long
213Creative Filtered - Not Allowed in PMP Deal
1001Multi-Bid - Bid Not Selected
1010Creative Filtered - Malware

Working with Multi-size Bid Requests

OpenX allows its publishers to support creatives for multiple ad sizes on a single impression opportunity and sends a single bid request for each ad size. You can choose to consolidate those ad sizes in to a single request using the format object.

To be able to return bids for multiple sizes in a single impression opportunity:

  • Make sure your bidding application logic can ingest all the sizes transmitted in the array of the format object in OpenRTB 2.4.
  • Ask your Platform Development Manager to enable format object support for your account.

The format object array includes widths and heights, so you must include bid.w and bid.h values in the bid response. For example, a bid request includes a banner populated with a format object that indicates availability of a 728x90, 320x50, and 160x60 creative:

"banner": {
            "format": [
                {"w": 728, "h": 90},
                {"w": 320, "h": 50},
                {"w": 160, "h": 60}


You can submit a bid for any one of the ad sizes, or a multi-bid for several sizes.