Prebid Server | Endpoints | /openrtb2/auction

POST /openrtb2/auction

• Sample Request
• Sample Response
  • Fledge Auctions
• OpenRTB Fields
  • IDs
    • request.id
    • request.source.tid
    • request.imp[].id
    • request.imp[].ext.tid
  • Expiration
  • Timeout
    • PBS-Go
    • PBS-Java
• OpenRTB Extensions
  • Conventions
  • OpenRTB Request Extensions
    • Global Bid Adapter Parameters
    • Bid Adjustments
      • Original Bid Adjustment Factors
      • Flexible Bid Adjustments
    • Targeting
    • Buyer UID
    • Native Request
    • Bidder Aliases
    • Bidder Alias GVL IDs
    • Stored Requests
    • Cache bids
      • Caching the entire bid
      • Caching just the VAST XML
    • GDPR
    • Interstitial support
    • Currency Support
    • Supply Chain Support
    • User IDs
    • EID Permissions
    • Rewarded Video
    • Create Transaction ID
    • Debug Flag
    • Trace Flag
    • Stored Responses
      • Impression Stored Auction Response ID
      • Impression Stored Auction Response JSON
      • Global Stored Auction Response JSON
      • Stored Bid Response IDs
    • First Party Data Support
      • Data Permissions
      • Bidder-Specific global FPD
      • Bidder-Specific Impression-Level FPD
    • Custom Targeting
    • MultiBid
    • Echo StoredRequest Video Attributes
    • Request Passthrough
    • Floors
    • Server Metadata
    • Analytics Extensions
      • Analytics adapter flags
      • Sending analytics tags to the client-side
    • Preferred Media Type
  • OpenRTB Response Extensions
    • Bidder Response Times
    • Bidder Errors
    • Ad Server Targeting
    • Debug Output
    • Original Bid CPM
    • Seat Non-Bid
• OpenRTB Ambiguities
• OpenRTB Differences
  • Allowed Bidders
  • Deprecated Properties
  • Determining Bid Security (http/https)
• HTTP Headers
• Prebid Server ORTB2 Extension Summary
• Further Reading

This endpoint runs an auction with the given OpenRTB 2.x bid request.

Sample Request

This is a sample OpenRTB 2.x bid request:

{
  "id": "some-request-id",
  "test": 1,
  "site": {
    "page": "prebid.org"
  },
  "imp": [{
    "id": "some-impression-id",
    "banner": {
      "format": [{
        "w": 600,
        "h": 500
      }, {
        "w": 300,
        "h": 600
      }]
    },
    "ext": {
      "prebid": {
        "bidder": {
          "bidderA": {
            "placement": 12345
          }
        }
      }
    }
  }],
  "tmax": 500
}

Additional examples can be found in endpoints/openrtb2/sample-requests/valid-whole.

Sample Response

This endpoint will respond with either:

• An OpenRTB 2.x bid response, or
• HTTP 400 if the request is malformed, or
• HTTP 503 if the account or app specified in the request is blacklisted

This is a corresponding sample response to a sample bid request:

{
  "id": "some-request-id",
  "seatbid": [{
    "seat": "bidderA",
    "bid": [{
      "id": "145556724130495288",
      "impid": "some-impression-id",
      "price": 0.01,
      "adm": "<script type=\"application/javascript\">...</script>",
      "adid": "107987536",
      "adomain": [
        "biddera.com"
      ],
      "iurl": "https://biddera.com/cr?id=107987536",
      "cid": "3532",
      "crid": "107987536",
      "w": 600,
      "h": 500,
      "ext": {
        "prebid": {
          "type": "banner",
          "video": {
            "duration": 0,
            "primary_category": ""
          }
        },
        "bidder": {
          "bidderA": {
            "brand_id": 1,
            "auction_id": 7311907164510136364,
            "bidder_id": 2,
            "bid_ad_type": 0
          }
        }
      }
    }]
  }],
  "cur": "USD",
  "ext": {
    "responsetimemillis": {
      "bidderA": 10
    },
    "tmaxrequest": 500
  }
}

Fledge Auctions

Fledge is an experimental approach to running online ad auctions with enhanced privacy.

Prebid Server’s support for Fledge is a passthrough:

1. If the request contains imp.ext.ae: 1
2. Bid adapters may respond with ‘auction config’ that’s placed in ext.prebid.fledge.auctionconfigs[].

The auction config must then be used by the client. See the Prebid.js PAAPI for GPT module for more information.

OpenRTB Fields

Prebid Server accepts all OpenRTB 2.x fields and passes them in the request to all bid and analytics adapters. Some fields are processed by Prebid Server in the following ways:

IDs

Prebid Server has the ability to fill in key IDs in the request.

request.id

if host config generate_request_id (Go) / generate-storedrequest-bidrequest-id (Java) is true
    if $.id is not set, generate a random value
    if the storedrequest is from AMP or from ext.prebid.storedrequest, then replace any existing $.id with a random value
if $.id contains "", replace that macro with a random value

request.source.tid

PBS-Go - this will change once issue 2727 is implemented to link the transmitTid activity.

if source.tid is not set:
   set source.tid to a random UUID
if host config auto_gen_source_tid (Go) / generate-storedrequest-bidrequest-id (Java) is true
    if the storedrequest is from AMP or from a top-level stored request (ext.prebid.storedrequest), then replace any existing $.source.tid with a random value
if $.source.tid contains "", replace that macro with a random value

PBS-Java

if source.tid is not set and the transmitTid activity is allowed:
   set source.tid to a random UUID
if host config generate-storedrequest-bidrequest-id config is true and the transmitTid activity is allowed
    if the storedrequest is from AMP or from a top-level stored request (ext.prebid.storedrequest), then replace any existing $.source.tid with a random value
if $.source.tid contains "", replace that macro with a random value

Note: the request parameter ext.prebid.createtids can override the transmitTids activity.

request.imp[].id

if host config generate-storedrequest-bidrequest-id config is true
    if any $.imp[].id is missing, set it to a random 16-digit string. (Note: this wasn't in issue 1507)
    if the storedrequest is from AMP **or** from a top-level stored request (ext.prebid.storedrequest), confirm that all $.imp[].id fields in the request are different. If not different, re-number them all starting from "1".

request.imp[].ext.tid

PBS-Go - this will change once issue 2727 is implemented to link the transmitTid activity.

if imp[n].ext.tid is not set:
       set imp[n].ext.tid to a randomly generated UUID
   if host config generate-storedrequest-bidrequest-id config is true
       if the storedrequest is from AMP or from ext.prebid.storedrequest, then replace any existing $.imp[n].ext.tid with a random value
if $.imp[n].ext.tid contains "", replace that macro with a random value

PBS-Java

for each imp:
   if imp[n].ext.tid is not set and the transmitTid activity is allowed:
       set imp[n].ext.tid to a randomly generated UUID
   if host config generate-storedrequest-bidrequest-id config is true and the transmitTid activity is allowed
       if the storedrequest is from AMP or from a top-level stored request (ext.prebid.storedrequest), then replace any existing $.imp[n].ext.tid with a random value
  if $.imp[n].ext.tid contains "", replace that macro with a random value

Note: the request parameter ext.prebid.createtids can override the transmitTids activity.

Expiration

The imp[].exp field is an “Advisory as to the number of seconds that may elapse between the auction and the actual impression.”

This field is used in slightly different ways by PBS-Go and PBS-Java:

PBS-Go

How long an item is stored in Prebid Cache is determined by this hunt path:

1. bidResponse.seatbid[].bid[].exp + 60: as set by the bidder’s adapter
2. request.imp[].exp + 60: as set by the incoming request
3. account config: cache_ttl.{banner,video,native,audio} + 60
4. global config: cache.default_ttl_seconds.{banner,video,native,audio} + 60

A 60-second buffer is added to make sure cache retrievals work towards the end of the cache period.

PBS-Java

How long an item is stored in Prebid Cache is determined by this hunt path:

1. bidResponse.seatbid[].bid[].exp: set by the bidder’s adapter
2. request.imp[].exp: set by the incoming request
3. request.ext.prebid.cache.{bids,vastxml}.ttlseconds
4. account config: {banner,video}-cache-ttl
5. global config: cache.{banner,video}-ttl-seconds

Timeout

The OpenRTB 2.5 tmax field defines how long Prebid Server has to process the request before the client will stop waiting.

This field is used in different ways by PBS-Go and PBS-Java:

PBS-Go

Hosts can configure auction_timeouts_ms and tmax_adjustments to enable the utilization of tmax in auction endpoints.

The auction_timeouts_ms parameter comprises default and max values. These values serve the purpose of determining the tmax duration PBS has for processing an auction request.

• If tmax value is not specified or is set to 0 in the auction request, PBS will use the default value configured by the host (auction_timeouts_ms.default) as the tmax.
• If tmax value specified in the auction request exceeds the maximum value defined by the host (auction_timeouts_ms.max), PBS will use host defined max (auction_timeouts_ms.max) as tmax.

The resultant tmax, as determined by the above rules is employed in conjunction with the tmax_adjustments to estimate the tmax value for bidders i.e bidder_tmax. This estimated value indicates the time allotted for bidders to respond to a bid request.

The tmax_adjustments parameter encompasses the following values:

• enabled (required): indicates whether the estimation of bidder_tmax should be enabled or not. Hosts can set it to “false” to disable the estimation of bidder_tmax.
• bidder_network_latency_buffer_ms: accounts for network delays that may occur between PBS and the bidder servers. A value of 0 indicates that no network latency buffer should be accounted for bidder_tmax calculation.
• bidder_response_duration_min_ms (required): minimum amount of time that PBS can expect to receive response from a bidder server.
• pbs_response_preparation_duration_ms (required): defines time needed for PBS to process all the responses from the bidders and generate the final response for a request.

Additionally, PBS takes into account the request_processing_time when estimating the bidder_tmax value. The request_processing_time represents the duration PBS takes to process a specific auction request before sending it to the bidder servers. It’s important to note that the request_processing_time is calculated at runtime.

PBS won’t send a request to the bidder if the calculated bidder_tmax is less than the pbs_response_preparation_duration_ms.

To summarize the process:

• If request.tmax is 0:

  tmax = auction_timeouts_ms.default
  

• If request.tmax is set to a large value, PBS attempts to cap tmax:

  tmax = min(request.tmax, auction_timeouts_ms.max)
  

• bidder_tmax is calculated as follows:

  bidder_tmax = tmax - request_processing_time - bidder_network_latency_buffer_ms - bidder_response_duration_min_ms
  

• If bidder_tmax is less than pbs_response_preparation_duration_ms, the request is not sent to the bidder server.

• In case tmax_adjustments.enabled is set to false, PBS continues to apply its rules for determining tmax, but bidder_tmax will not be calculated, and PBS will consistently send the request to the bidder server.

PBS-Java

Core concepts:

• request_tmax: what the incoming ORTB request defines as tmax (as milliseconds)
• biddertmax_max: controls that upstream doesn’t tell us ridiculous values. In milliseconds. (configuration auction.biddertmax.max)
• biddertmax_min: it’s not worth calling bidders and give them less time than this number of milliseconds (configuration (auction.biddertmax.min). Note: we recommend this value be at least 150 ms)
• biddertmax_percent: a lower number means more buffer for network delay. Host companies should set this to a lower value in regions where the network connections are slower. (configuration auction.biddertmax.percent)
• tmax_upstream_response_time: the amount of time (in ms) that PBS needs to respond to the original caller (configuration auction.tmax-upstream-response-time)
• processing_time: PBS calculation for how long it’s been since the start of the request up to the point where the bidders are called
• bidder_tmax: this is what PBS-core tells the bidders they have to respond. The conceptual formula is: capped(request_tmax)*biddertmax_percent - processing_time - tmax_upstream_response_time ==> must be at least the configured min
• enforced_tmax: this is long PBS-core actually gives the bidders: capped(request_tmax)- processing_time - tmax_upstream_response_time ==> cannot be lower than bidder_tmax

The full formulas:

bidder_tmax=max(calculated_tmax, biddertmax_min)=max((min(request_tmax,biddertmax_max)*biddertmax_percent)-processing_time - tmax_upstream_response_time, biddertmax_min)

enforced_tmax=max(calculated_enforcement,bidder_tmax)=max(min(request_tmax,biddertmax_max)-processing_time - tmax_upstream_response_time , bidder_tmax)

OpenRTB Extensions

Conventions

OpenRTB 2.x permits exchanges to define their own extensions to any object from the spec. These fall under the ext field of JSON objects.

If ext is defined on an object, Prebid Server uses the following conventions:

1. ext in “request objects” uses ext.prebid and/or ext.{anyBidderCode}.
2. ext on “response objects” uses ext.prebid and/or ext.bidder. The only exception here is the top-level BidResponse, because it’s bidder-independent.

ext.{anyBidderCode} and ext.bidder extensions are defined by bidders. ext.prebid extensions are defined by Prebid Server.

Prebid Server supports the following “standard” industry extensions:

• request.regs.ext.gdpr and request.user.ext.consent – To support GDPR
• request.regs.ext.us_privacy – To support CCPA
• request.site.ext.amp – To identify AMP as the request source
• request.user.ext.eids – To support Extended Identifiers
• request.app.ext.source and request.app.ext.version – To support identifying the displaymanager/SDK in mobile apps. If given, we expect these to be strings.

OpenRTB Request Extensions

Global Bid Adapter Parameters

PBS supports two scenarios:

1. If a bid adapter has a parameter that is the same across all imp[] entries, it can be supplied on ext.prebid.bidderparams.BIDDER:

{
  "ext": {
    "prebid": {
      "bidderparams": {
        "bidderA": {
          "key1": "some-value-1",
          "key2": {
            "version": 3.3,
            "profileid": 1234
          }
        },
        "bidderB": {
          "key3": "some-value-3"
        }
      }
    }
  }
}

Bid adapters do not need to read this data from ext.prebid. PBS will merge the attributes to each imp[] in the request so the adapter can read them normally.

2. If a bid adapter has a parameter that alters its runtime behavior, but is not a formal parameter, it can be supplied on ext.prebid.bidders.BIDDER. The adapter will see this on ext.prebid.bidders.bidder.

{
  "ext": {
    "prebid": {
      "bidders": {
        "bidderA": {
          "option": "value"
        },
        "bidderB": {
          "option": "value"
        }
      }
    }
  }
}

Bid Adjustments

There are two ways PBS can be instructed to adjust bids:

1. The original bidadjustmentfactors approach is simpler and allows for percentage-based adjustments based on bidder and mediatype.
2. The more powerful bidadjustments feature allows for percentage, absolute, and static adjustments based on bidder, mediatype and deal IDs.

If both bidadjustments and bidadjustmentfactors are specified, the bidadjustments (newer approach) takes precedence.

Original Bid Adjustment Factors

Bidders are encouraged to make Net bids. However, there’s no way for Prebid to enforce this. If you find that some bidders use Gross bids, publishers can adjust for it with request.ext.prebid.bidadjustmentfactors:

{
  "ext": {
    "prebid": {
      "bidadjustmentfactors": {
        "bidderA": 0.9,
        "bidderB": 0.8
      }
    }
  }
}

This may also be useful for publishers who want to account for different discrepancies with different bidders.

It’s also possible to define different bid adjustment factors by mediatype, which can be helpful to adjust discrepancies that differ across mediatypes:

{
  "ext": {
    "prebid": {
      "bidadjustmentfactors": {
        "bidderA": 0.9,
        "bidderB": 0.8,
        "mediatypes": {
          "banner": {
            "bidderA": 0.8
          },
          "video-outstream": {
            "bidderC": 0.9
          },
          "video": {
            "bidderB": 0.85
          }
        }
      }
    }
  }
}

Note that video-outstream is defined to be imp[].video requests where imp[].video.placement is greater than 1.

Flexible Bid Adjustments

A more powerful approach to adjusting bid values can be specifed on the request or in account config. Here’s the general format:

{
  "ext": {
    "prebid": {
      "bidadjustments": {
        "mediatype": {
           MEDIATYPE: {
             BIDDER: {
               DEAL: [ {"adjtype": ADJTYPE, "value": ADJVALUE, "currency": CURRENCY} ]
             }
           }
         }
       }
    }
  }
}

Where:

• MEDIATYPE can be ‘banner’, ‘video-instream’, ‘video-oustream’, ‘native’, ‘audio’, or a wildcard (*)
• BIDDER can be a biddercode or a wildcard (*)
• DEAL can be a dealID or a wildcard (*)
• ADJTYPE can be ‘multiplier’, ‘cpm’ or ‘static’
• ADJVALUE is a float value. See the table below for more details.
• CURRENCY is a 3 character currency code, e.g. “EUR”. This is required for some ADJTYPEs.

Note that the specific adjustments are after the deal level and are an array of adjustments. Most commonly there will be only one entry in the array, but allowing it to have multiple entries can meet some advanced adjustment use cases. The next couple of sections provide detail on the input values.

MediaType

Adjustment Types and Values

Notes

• In all cases, the ‘value’ is required.
• Any validation failure will skip the whole bid adjustment operation
• The system will attempt to merge request-level and account-level bid adjustments. If this fails it will try to use only the account bid adjustments.
• If there’s a validation error, a debug message will be added and a sample will be logged to the PBS log file.

Example

Here’s an example showing a couple of use cases:

{
  "ext": {
    "prebid": {
      "bidadjustments": {
          "mediatype": {
              "banner": {
                  // decrement banner bids from bidderA by 10%
                  "bidderA": {
                      "*" : [ {"adjtype": "multiplier", "value": 0.9} ]
                  },
                  "*": {  // wildcard bidder only matches if there isn't a more direct match
                      // bids on deal 111111 are always exactly $3.00
                      "111111": [{
                          "adjtype": "static", "value": 3.00, "currency": "USD"
                      }],
                      // otherwise, always decrement banner bids by $0.10
                      "*": [{
                            "adjtype": "cpm", "value": 0.1, "currency": "USD"
                      }]
                  }
              },
              "video-instream": {
                  // for video bids, take 80% of the bid value and add $0.18.
                  "*": { // all bidders
                     "*": [{ // all deals
                         "adjtype": "multiplier", "value": 0.80
                     }, {
                         "adjtype": "cpm", "value": 0.18, "currency": "USD"
                     }]
                  }
              }
          }
       }
    }
  }
}

Note that these bidadjustments can also be specified in the PBS account config in auction.bidadjustments

Targeting

Targeting refers to strings that are sent to the adserver to make header bidding possible.

request.ext.prebid.targeting is an optional property that causes Prebid Server to set these params on the response at response.seatbid[i].bid[j].ext.prebid.targeting.

Request format (optional param request.ext.prebid.targeting)

{
  "ext": {
    "prebid": {
      "targeting": {
        "pricegranularity": {
          "precision": 2,
          "ranges": [{
            "max": 20.00,
            "increment": 0.10 // This is equivalent to the deprecated
                              // "pricegranularity": "medium"
          }]
        },
        "includewinners": true,     // Optional param defaulting to false
        "includebidderkeys": false, // Optional param defaulting to false
        "includeformat": false,     // Optional param defaulting to false
        "preferdeals": true         // Optional param defaulting to false
        "alwaysincludedeals": true  // Optional param defaulting to false
      }
    }
  }
}

The list of price granularity ranges must be given in order of increasing max values. If precision is omitted, it will default to 2. The minimum of a range will be 0 or the previous max. Any cpm above the largest max will go in the max pricebucket.

For backwards compatibility the following strings will also be allowed as price granularity definitions. There is no guarantee that these will be honored in the future. “One of [‘low’, ‘med’, ‘high’, ‘auto’, ‘dense’]” See price granularity definitions.

One of “includewinners” or “includebidderkeys” should be true if you want targeting - both default to false if unset. If both are false, then no targeting keys will be set, which is better configured by omitting targeting altogether.

The parameter “includeformat” indicates the type of the bid (banner, video, etc) for multiformat requests. It will add the key hb_format and/or hb_format_{bidderName} as per “includewinners” and “includebidderkeys” above.

MediaType PriceGranularity - when a single OpenRTB request contains multiple impressions with different mediatypes, or a single impression supports multiple formats, the different mediatypes may need different price granularities. If mediatypepricegranularity is present, pricegranularity would only be used for any mediatypes not specified.

For example:

{
  "ext": {
    "prebid": {
      "targeting": {
        "pricegranularity": {                 // use this for banner and native
          "ranges": [
              {"max": 20, "increment": 0.5}
            ]
        },
        "mediatypepricegranularity": {        // video gets a different set of ranges     
          "video": {
            "ranges": [
              {"max": 10, "increment": 1},
              {"max": 20, "increment": 2},
              {"max": 50, "increment": 5}
            ]
          }
        }
      },
      "includewinners": true
    }
  }
}

Response format (returned in bid.ext.prebid.targeting)

{
  "seatbid": [{
    "bid": [{
      ...
      "ext": {
        "prebid": {
          "targeting": {
            "hb_bidder_{bidderName}": "The seatbid.seat which contains this bid",
            "hb_size_{bidderName}": "A string like '300x250' using bid.w and bid.h for this bid",
            "hb_pb_{bidderName}": "The bid.cpm, rounded down based on the price granularity."
          }
        }
      }
    }]
  }]
}

The winning bid for each request.imp[i] will also contain hb_bidder, hb_size, and hb_pb (with no {bidderName} suffix). To prevent these keys, set request.ext.prebid.targeting.includeWinners to false.

NOTES:

• Targeting keys are limited to 20 characters. If {bidderName} is too long, the returned key will be truncated to only include the first 20 characters.

Buyer UID

Each Bidder should receive their own ID in the request.user.buyeruid property. Prebid Server has three ways to populate this field. In order of priority:

1. If the request payload contains request.user.buyeruid, then that value will be sent to all Bidders. In most cases, this is probably a bad idea.

2. The request payload can store a buyeruid for each Bidder by defining request.user.ext.prebid.buyeruids like so:

    {
      "user": {
        "ext": {
          "prebid": {
            "buyeruids": {
              "bidderA": "some-biddera-id",
              "bidderB": "some-bidderb-id"
            }
          }
        }
      }
    }
   

   Prebid Server’s core logic will preprocess the request so that each Bidder sees their own value in the request.user.buyeruid field.

3. Prebid Server will use its Cookie to map IDs for each Bidder.

   If you’re using Prebid.js, this is happening automatically.

   If you’re using another client, you can populate the Cookie of the Prebid Server host with User IDs for each Bidder by using the /cookie_sync endpoint, and calling the URLs that it returns in the response.

Native Request

For each native request, the assets object’s id field is optional and if not defined, Prebid Server will set this automatically, using the index of the asset in the array as the ID.

Bidder Aliases

Requests can define Bidder aliases if they want to refer to a Bidder by a separate name. This can be used to request bids from the same Bidder with different params. For example:

{
  "imp": [{
    "id": "some-impression-id",
    "video": {
      "mimes": ["video/mp4"]
    },
    "ext": {
      "appnexus": {
        "placementId": 123
      },
      "districtm": {
        "placementId": 456
      }
    }
  }],
  "ext": {
    "prebid": {
      "aliases": {
        "districtm": "appnexus"
      }
    }
  }
}

For all intents and purposes, the alias will be treated as another Bidder. This new Bidder will behave exactly like the original, except that the Response will contain separate SeatBids, and any Targeting keys will be formed using the alias’ name.

If an alias overlaps with a core Bidder’s name, then the alias will take precedence. This prevents breaking API changes as new Bidders are added to the project.

For example, if the Request defines an alias like this:

"aliases": {
  "appnexus": "rubicon"
}

then any imp.ext.appnexus params will actually go to the rubicon adapter. It will become impossible to fetch bids from AppNexus within that Request.

Bidder Alias GVL IDs

For publishers that use Prebid Server as part of their GDPR/TCF strategy, it can be important to define the Global Vendor List (GVL) ID with an alias.

To do this, just set ext.prebid.aliasgvlids alongside ext.prebid.aliases:

"ext": {
  "prebid": {
    "aliases": {
      "newAlias": "originalBidderCode"
    },
    "aliasgvlids": {
      "newAlias": 11111
    }
  }
}

Stored Requests

request.imp[i].ext.prebid.storedrequest incorporates a Stored Request from the server.

A typical storedrequest value looks like this:

{
  "imp": [{
    "ext": {
      "prebid": {
        "storedrequest": {
          "id": "some-id"
        }
      }
    }
  }]
}

For more information, see the docs for Stored Requests.

Cache bids

Bids can be temporarily cached on the server by sending instructions in request.ext.prebid.cache:

{
  "ext": {
    "prebid": {
      "cache": {
        "bids": {},
        "vastxml": {}
      }
    }
  }
}

Both bids and vastxml are optional, but one of the two is required if you want to cache bids. This property will have no effect unless request.ext.prebid.targeting is also set in the request.

Caching the entire bid

If the ext.prebid.cache.bids object is present, Prebid Server will make a best effort to cache the entire bid object server-side and return the cache location in two places:

1. OpenRTB seatbid.bid.ext.prebid.cache.bids

        {
          "seatbid": [
            "bid": [
              ...
              "ext": {
                "prebid": {
                  "cache": {
                    "bids": {
                      "url": "https://example.com:443/cache?uuid=385b283c-22cb-49a0-8c0b-8b88c49d9fe9",
                      "cacheId": "385b283c-22cb-49a0-8c0b-8b88c49d9fe9"
                    }
                  }
                }
              }
            ]
          ]
        }
   

2. Extra bid.ext.prebid.targeting keys:

   • hb_cache_id: the cache ID for the highest overall bid in each imp.
   • hb_cache_host: the hostname where the cacheId may be retrieved.
   • hb_cache_path: the path where the cacheId may be retrieved. https://hb_cache_host/hb_cache_path?uuid=hb_cacheId
   • hb_cache_id_{bidderName}: the cache ID for the highest bid from {bidderName} in each imp.

If caching succeeded, the value will be a UUID which can be used to fetch Bid JSON from Prebid Cache. The keys may not exist if the host company’s cache is full, having connection problems, etc.

This option is mainly intended for Prebid Mobile setups where bids aren’t cached client-side.

Caching just the VAST XML

This option is mainly intended for video players that need a URL that returns a VAST XML body.

If the ext.prebid.cache.vastxml object is present, Prebid Server will make a best effort to cache just the VAST XML server-side and return the cache location in two places:

1. OpenRTB seatbid.bid.ext.prebid.cache.vastXml

        {
          "seatbid": [
            "bid": [
              ...
              "ext": {
                "prebid": {
                  "cache": {
                    "vastXml": {
                      "url": "https://example.com:443/cache?uuid=385b283c-22cb-49a0-8c0b-8b88c49d9fe9",
                      "cacheId": "385b283c-22cb-49a0-8c0b-8b88c49d9fe9"
                    }
                  }
                }
              }
            ]
          ]
        }
   

2. Extra bid.ext.prebid.targeting keys:

   • hb_uuid: the cache ID for the highest overall video bid in each imp.
   • hb_cache_host: the hostname where the UUID may be retrieved.
   • hb_cache_path: the path where the UUID may be retrieved. ex: https://hb_cache_host/hb_cache_path?uuid=hb_uuid
   • hb_uuid_{bidderName}: the cache ID for the highest video bid from {bidderName} in each imp.

In addition to the caveats noted for cache.bids, these will exist only if there are video bids. If the keys exist, the values can be used to fetch the bid’s VAST XML from Prebid Cache directly.

GDPR

Prebid Server supports the IAB’s GDPR recommendations.

This adds two optional properties:

• request.user.ext.consent: Is the consent string required by the IAB standards.
• request.regs.ext.gdpr: Is 0 if the caller believes that the user is not under GDPR, 1 if the user is in GDPR-scope, and undefined if the caller is uncertain.

These fields will be forwarded to each Bidder, so they can decide how to process them.

Interstitial support

Additional support for interstitials is enabled through the addition of two fields to the request: device.ext.prebid.interstitial.minwidthperc and device.ext.prebid.interstitial.minheightperc. The values will be numbers that indicate the minimum allowed size for the ad, as a percentage of the base side. For example, a width of 600 and "minwidthperc": 60 would allow ads with widths from 360 to 600 pixels inclusive.

Example:

{
  "imp": [{
    ...
    "banner": { ... },
    "instl": 1,
    ...
  }],
  "device": {
    ...
    "h": 640,
    "w": 320,
    "ext": {
      "prebid": {
        "interstitial": {
          "minwidthperc": 60,
          "minheightperc": 60
        }
      }
    }
  }
}

If PBS receives a request for an interstitial imp and these parameters are set, it will rewrite the format object within the interstitial imp. If the format array’s first object is a size, PBS will take it as the max size for the interstitial. If that size is 1x1, it will look up the device’s size and use that as the max size. If the format is not present, it will also use the device size as the max size (1x1 support so that you don’t have to omit the format object to use the device size).

PBS with interstitial support will come preconfigured with a list of common ad sizes,preferentially organized by weighing the larger and more common sizes first. But no guarantees to the ordering will be made. PBS will generate a new format list for the interstitial imp by traversing this list and picking the first 10 sizes that fall within the imp’s max size and minimum percentage size. There will be no attempt to favor aspect ratios closer to the original size’s aspect ratio. The limit of 10 is enforced to ensure we don’t overload bidders with an overlong list. All the interstitial parameters will still be passed to the bidders, so they may recognize them and use their own size matching algorithms if they prefer.

Currency Support

To set the desired ‘ad server currency’, use the standard OpenRTB cur attribute. Note that Prebid Server only looks at the first currency in the array.

"cur": ["USD"]

If you want or need to define currency conversion rates (e.g. for currencies that your Prebid Server doesn’t support), define ext.prebid.currency.rates.

"ext": {
  "prebid": {
    "currency": {
      "rates": {
        "USD": { "UAH": 24.47, "ETB": 32.04 }
      }
    }
  }
}

If it exists, a rate defined in ext.prebid.currency.rates has the highest priority. If a currency rate doesn’t exist in the request, the external file will be used.

An additional option is usepbsrates. When true, this flag indicates that dynamic currency exchange rates should be preferred over any supplied static rates. When false, it indicates that dynamic exchange rates should not be used. The default is ‘true’.

Supply Chain Support

Basic supply chains are passed to Prebid Server on source.ext.schain and passed through to bid adapters. Prebid Server does not currently offer the ability to add a node to the supply chain.

Bidder-specific schains:

"ext.prebid.schains": [
   { "bidders": ["bidderA"], "schain": { SCHAIN OBJECT 1}},
   { "bidders": ["*"], "schain": { SCHAIN OBJECT 2}}
]

In this scenario, Prebid Server sends the first schain object to bidderA and the second schain object to everyone else.

If there’s already an source.ext.schain and a bidder is named in ext.prebid.schains (or covered by the wildcard condition), ext.prebid.schains takes precedent.

User IDs

Prebid Server adapters can support the Prebid.js User ID modules by reading the following extensions and passing them through to their server endpoints:

{
  "user": {
    "ext": {
      "eids": [{
        "source": "adserver.org",
        "uids": [{
          "id": "111111111111",
          "ext": {
            "rtiPartner": "TDID"
          }
        }]
      },
      {
        "source": "pubcid.org",
        "id":"11111111"
      }]
    }
  }
}

EID Permissions

Publishers can constrain which bidders receive which user.ext.eids entries. See the Prebid.js user ID permissions reference for background.

{
  "ext": {
    "prebid": {
      "data": {
        "eidpermissions": [
          {"source": "sharedid.org", "bidders": ["*"]},  // * is the default
          {"source": "neustar.biz",  "bidders": ["bidderB"]},
          {"source": "id5-sync.com", "bidders": ["bidderA","bidderC"]}
        ]
      }
    }
  }
}

ext.prebid.data.eidpermissions is an array of objects that can contain these attributes:

Rewarded Video

To be deprecated for request.imp[].rwdd introduced in OpenRTB 2.6.

Rewarded video is a way to incentivize users to watch ads by giving them ‘points’ for viewing an ad. A Prebid Server client can declare a given adunit as eligible for rewards by declaring imp.ext.prebid.is_rewarded_inventory:1.

Create Transaction ID

The request can contain the global createtids flag to control the transmitTid Activity Control.

ext.request.createtids: false

If the value is false, the transmitTid activity is overridden to “denied”, which means bid adapters will not get unique transaction IDs. If not specified, then the value of the transmitTid activity for the account is used. The overall default value it true, which translates to “allow” the generation of TIDs.

See the endpoint documentation on IDs for details on how PBS creates the various IDs including transaction IDs.

Debug Flag

The OpenRTB test flag has a special meaning that bidders may react to: they may not perform a normal auction, or may not pay for test requests.

You can turn on the extra Prebid Server debug log without the formal test behavior by instead setting ext.prebid.debug: true.

Trace Flag

You can turn on additional Prebid Server tracing by setting ext.prebid.trace to either “verbose” or “basic”. This provides additional information for modules.

Stored Responses

While testing SDK and video integrations, it’s often difficult, to get consistent responses back from bidders that cover a range of scenarios like different CPM values, deals, etc. Prebid Server supports a debugging workflow in several ways:

1. A impression-level stored auction response that covers multiple bidder responses for this impression. The contents of the stored auction response can be either:
   1. An id that retrieves an object is assumed to be a full OpenRTB response, causing the system to completely bypass bid adapters.
   2. A JSON object that’s simply used as the contents of the ORTB response.
2. Multiple stored bid responses at the bidder adapter level. The contents of this object are bidder-specific and passed through the code of the bid adapter, representing a true end-to-end flow within Prebid Server.
3. A global stored auction response that lets the caller override the entire response for multiple impressions.

Impression Stored Auction Response ID

Provides a way to override multiple bidder responses for this impression, retrieving the contents from a local data store. For example:

  "imp": [{ "ext": { "prebid": {
          "storedauctionresponse": { "id": "1111111111" }
  }}}]

When a storedauctionresponse ID is specified:

• the rest of the imp.ext.prebid block is irrelevant and ignored
• nothing is sent to any bidder adapter for that imp
• the response retrieved is assumed to be the entire contents of the seatbid object corresponding to that impression.

For example, this request:

{
  "test": 1,
  "tmax": 500,
  "id": "test-auction-id",
  "app": { ... },
  "ext": {
    "prebid": {
      "targeting": {},
      "cache": {
        "bids": {}
      }
    }
  },
  "imp": [
    {
      "id": "a",
      "ext": {
        "prebid": {
          "storedauctionresponse": { "id": "1111111111" }
        }
      }
    },
    {
      "id": "b",
      "ext": {
        "prebid": {
          "storedauctionresponse": { "id": "22222222222" }
        }
      }
    }
  ]
}

might result in this response, assuming that the ids exist in the appropriate DB table read by Prebid Server:

{
  "id": "test-auction-id",
  "seatbid": [
    {
      "bid": [{
        // BidderA bid from storedauctionresponse=11111111111
      },{
        // BidderA bid from storedauctionresponse=22222222222
      }],
      "seat": "bidderA"
    },
    {
      "bid": [{
        // BidderB bid from storedauctionresponse=11111111111
      },{
        // BidderB bid from storedauctionresponse=22222222222
      }],
      "seat": "bidderB"
    }
  ]
}

In the above example, the contents of the storedauctionresponse entry is an array of ortb2 seatbid objects. e.g.

[
  {
    "bid": [{
        "impid": "a", // doesn't have to match the request
        ... bid 1 ...
    },{
        "impid": "b", // doesn't have to match the request
        ... bid 2 ...
    }],
    "seat": "bidderA"
  },{
    "bid": [{
        "impid": "a", // doesn't have to match the request
        ... bid 1 ...
    },{
        "impid": "b", // doesn't have to match the request
        ... bid 2 ...
    }],
    "seat": "bidderB"
  }
]

Impression Stored Auction Response JSON

(PBS-Java 3.13+)

Provides a way to override multiple bidder responses for this impression, with the contents supplied on the request itself. This can be useful for dynamically debugging apps where creating stored response database entries with different creatives or prices could be time consuming. For example:

  "imp": [{ "ext": { "prebid": {
          "storedauctionresponse": { "seatbidobj": { ... contents of this object are appended to the response.seatbid array ... } }
  }}}]

When storedauctionresponse JSON is specified:

• the rest of the imp.ext.prebid block is irrelevant and ignored
• nothing is sent to any bidder adapter for that imp
• the JSON in the request is assumed to be the entire contents of the seatbid object corresponding to that impression.

For example, this request:

{
  "test": 1,
  "tmax": 500,
  "id": "test-auction-id",
  "app": { ... },
  "ext": {
    "prebid": {
      "targeting": {},
      "cache": {
        "bids": {}
      }
    }
  },
  "imp": [
    {
      "id": "a",
      "ext": {
        "prebid": {
          "storedauctionresponse": { "seatbidobj": {"bid": [{"h": 250,"w": 300,"id": "f227a07f-1579-4465-bc5e-5c5b02a0c180","adm": "<img src=\"https://files.prebid.org/creatives/prebid300x250.png\" border=\"0\" alt=\"\" />\n","ext": {"prebid": {"type": "banner"}},"crid": "11111","impid": "##PBSIMPID##","price": 1.0}],"seat": "bidderA","group": 0}}
        }
      }
    },
    {
      "id": "b",
      "ext": {
        "prebid": {
          "storedauctionresponse": { "seatbidobj": {"bid": [{"h": 50,"w": 300,"id": "f227a07f-1579-4465-bc5e-5c5b02a0c180","adm": "<img src=\"https://files.prebid.org/creatives/prebid300x50.png\" border=\"0\" alt=\"\" />\n","ext": {"prebid": {"type": "banner"}},"crid": "22222","impid": "##PBSIMPID##","price": 2.0}],"seat": "bidderA","group": 0}}
        }
      }
    }
  ]
}

might result in this response:

{
  "id": "test-auction-id",
  "seatbid": [
    {
      "bid": [{
        // BidderA bid from storedauctionresponse seatbidobj on impid:'a'
      },{
        // BidderA bid from storedauctionresponse seatbidobj on impid:'b'
      }],
      "seat": "bidderA"
    }
  ]
}

Note: the ##PBSIMPID## macro is only supported in PBS-Java. Please use "replaceimpid":true for PBS-Go.

Global Stored Auction Response JSON

(PBS-Java 3.13+)

Provides a way to override the entire bid response, with the contents supplied on the request itself. This can be useful for dynamically debugging apps where creating stored response database entries with different creatives or prices could be time consuming. For example:

  { "ext": { "prebid": {
          "storedauctionresponse": { "seatbidarr": { ... contents of this object become the response.seatbid array ... } }
  }}}

When storedauctionresponse JSON is specified at the global level:

• all imp.ext.prebid.storedauctionresponse blocks are irrelevant and ignored
• nothing is sent to any bidder adapter
• the JSON in the request is assumed to be the entire contents of the seatbid response

For example, this request:

{
  "test": 1,
  "tmax": 500,
  "id": "test-auction-id",
  "app": { ... },
  "ext": {
    "prebid": {
          "storedauctionresponse": { "seatbidarr": [{"bid": [{"h": 250,"w": 300,"id": "f227a07f-1579-4465-bc5e-5c5b02a0c180","adm": "<img src=\"https://files.prebid.org/creatives/prebid300x250.png\" border=\"0\" alt=\"\" />\n","ext": {"prebid": {"type": "banner"}},"crid": "11111","impid": "##PBSIMPID##","price": 1.0}],"seat": "bidderA","group": 0},{"bid": [{"h": 50,"w": 300,"id": "f227a07f-1579-4465-bc5e-5c5b02a0c180","adm": "<img src=\"https://files.prebid.org/creatives/prebid300x50.png\" border=\"0\" alt=\"\" />\n","ext": {"prebid": {"type": "banner"}},"crid": "22222","impid": "##PBSIMPID##","price": 2.0}],"seat": "bidderA","group": 0}]},
      "targeting": {},
      "cache": {
        "bids": {}
      }
    }
  },
  "imp": [
    { "id": "a" },
    { "id": "b" }
  ]
}

might result in this response:

{
  "id": "test-auction-id",
  "seatbid": [
    {
      "bid": [{
        // BidderA bid from storedauctionresponse seatbidarr on impid:'a'
      },{
        // BidderA bid from storedauctionresponse seatbidarr on impid:'b'
      }],
      "seat": "bidderA"
    }
  ],
  "ext": {
    "warnings": {
      "prebid": [{
          "code": 999,
          "message": "no auction. response defined by storedauctionresponse"
        }
    ]}
  }
}

Note: the ##PBSIMPID## macro is only supported in PBS-Java. Please use "replaceimpid":true for PBS-Go.

Stored Bid Response IDs

In contrast to the storedauctionresponses above, using a storedbidresponse lets real auctions take place while the actual bidder response is overridden in such a way that it still exercises adapter code.

PBS removes imp.ext.prebid.bidder parameters for those bidders specified in storedbidresponse but if there’s a bidder present in imp.ext.prebid.bidder that’s doesn’t have a storedbidresponse specified, the adapter will be called as usual.

For example, this request:

{
  "test": 1,
  "tmax": 500,
  "id": "test-auction-id",
  "app": { ... },
  "ext": {
    "prebid": {
      "targeting": {},
        "cache": { "bids": {} }
    }
  },
  "imp": [
    {
      "id": "a",
      "ext": {
        "prebid": {
          "bidder: {
            "bidderA": { ... params ... },
            "bidderB": { ... params ... }
          },
          "storedbidresponse": [
            { "bidder": "BidderA", "id": "333333", "replaceimpid":true },
            { "bidder": "BidderB", "id": "444444", "replaceimpid":true },
          ]
        }
      }
    },
    {
      "id": "b",
      "ext": {
        "prebid": {
          "bidder: {
            "bidderA": { ... params ... },
            "bidderB": { ... params ... }
          },
          "storedbidresponse": [
            { "bidder": "BidderA", "id": "5555555", "replaceimpid":true }
            // note: no storedbidrespose for bidderB
          ]
        }
      }
    }
  ]
}

Could result in this response:

{
  "id": "test-auction-id",
  "seatbid": [
    {
      "bid": [{
        // contents of storedbidresponse=3333333 as parsed by bidderA adapter
      },{
        // contents of storedbidresponse=5555555 as parsed by bidderA adapter
      }],
      "seat": "bidderA"
    },
    {
      "bid": [{
        // contents of storedbidresponse=4444444 as parsed by bidderB adapter
      },{
        // actual bid response from bidderB
      }],
      "seat": "bidderB"
    }
  ]
}

Notes:

• The DB entries for this stored-response scenario are quite different: they need to be in whatever format the bid adapter’s endpoint responds with. i.e. the host company will need to capture an actual bid response from the specific bidders and enter it into the DB table.
• The replaceimpid parameter tells PBS to ignore the impid supplied in the DB and instead create/overwrite seatbid.bid.impid with the value that matches the incoming request. This simplifies debugging.
• replaceimpid doesn’t work in PBS-Java. Instead, the implementation there is to use the ##PBSIMPID## macro in the body of the stored response, which will be replaced by PBS-core.

See Prebid.org troubleshooting pages for how to utilize this feature within the context of the browser.

First Party Data Support

This is a standard way for the page (or app) to supply First Party Data and control which bidders have access to it.

Prebid defines several types of First Party Data (FPD):

1. Cross-impression contextual information. e.g. the content category of the page. This data goes in the site.ext.data object or the app.ext.data object.
2. User-level information. e.g. whether the user is a registered user. This data goes in user.ext.data.
3. Impression-level information. e.g. the Global Placement ID. This data goes in the imp.ext.data object.
4. Seller-Defined Audience (SDA) contextual data. This goes in site.data[] or app.data[] in accordance with the IAB segment taxonomy conventions.
5. SDA user data goes in user.data[] with the same conventions as the contextual data.

See below for how to specify these different types of data and how to define which bidders are allowed to receive which.

Data Permissions

This approach specifies whether the given bidder(s) are allowed to receive the global (contextual or user) FPD.

If a ext.prebid.data.bidders[] is specified, it means that {site,app}.ext.data and user.ext.data fields will only be passed to the named bidders. For example:

{
  "ext": {
    "prebid": {
      "data": { "bidders": [ "bidderA", "bidderB" ] }  // these are the bidders allowed to see the globsl FPD
    }
  }
}

For example:

{
  "ext": {
    "prebid": {
      "data": { "bidders": [ "bidderA", "bidderB" ] }  // these are the bidders allowed to see protected data
    }
  },
  "site": {
    "keywords": "",
    "search": "",
    "ext": {
      "data": { GLOBAL SITE DATA } // only seen by bidders named in ext.prebid.data.bidders[]
    }
  },
  "user": {
    "keywords": "",
    "geo": {},
    "ext": {
      "data": { GLOBAL USER DATA }  // only seen by bidders named in ext.prebid.data.bidders[]
    }
  },
  "imp": [
    {
      ...
      "ext": {
        "data": {
          ADUNIT SPECFIC CONTEXT DATA  // can be seen by all bidders
        }
      }
    }
  ]
}

Bidder-Specific global FPD

Bidder-specific global (i.e. cross-impression) data can be defined with ext.prebid.bidderconfig:

"ext": {
  "prebid": {
    "bidderconfig": [
      {
        "bidders": ["bidderA", "bidderB"],
        "config": {
           "ortb2": {
              "site": { ... },
              "user": { ... }
           }
        }
      },
      {
        "bidders": ["bidderC"],
        "config": {
           "ortb2": {
              "site": { ... },
              "user": { ... }
           }
        }
      }
    ]
  }
}

Prebid Server enforces data permissioning. So before passing values to the bidder adapters, the PBS core will:

1. Check for ext.prebid.bidderconfig
   1. If it exists, merge config.ortb2 into the bidder-specific request
2. As the OpenRTB request is being sent to each adapter:
   1. If ext.prebid.data.bidders exists in the original request and this bidder is on the list, then copy site.content.data, site.ext.data, app.ext.data, user.data, and user.ext.data to the bidder request – otherwise don’t copy those blocks. Remove ext.prebid.data.bidders from the bidder-specific request
   2. copy other objects as normal

Each adapter must be coded to read the values from the ortb and pass it to their endpoints appropriately.

Bidder-Specific Impression-Level FPD

When Prebid Server sees imp[].ext.prebid.imp.BIDDER, the behavior is to:

1. When passing this imp to that bidder, merge the contents of BIDDER into the imp
2. Remove the imp[].ext.prebid.imp object
3. Leave any imp[].ext.prebid.storedrequest object
4. The imp.ext.prebid.imp.BIDDER object name is case insensitive and supports aliases
5. If imp.ext.prebid.imp.BIDDER does not resolve to an actual bidder or alias in a case-insensitive way, it is ignored with a warning when in debug mode.
6. No validation is done on imp.ext.prebid.imp.BIDDER.ext except that imp.ext.prebid.imp.BIDDER.ext.prebid.BIDDER is removed.
7. The contents of imp.ext.prebid.imp.BIDDER takes precedence in the merge if the field already exists in the request.
8. The resulting imp object must be valid OpenRTB per the system schema.

Here’s an example showing a scenario showing a storedrequest-based scenario:

{
  imp: [{
    ext: {
      prebid: {
        storedrequest: { id: "sr1" },  // for the first imp, pull bidders out of a storedrequest
        imp: {
          bidderA: {
            pmp: {
              deals: [{ id:"dealA" }]      // apply this deal to bidderA
            }
          }
        }
      }
  },{
    ext: {
      prebid: {
        storedrequest: { id: "sr2" }, // for the second imp, pull bidders out of a different storedrequest
        imp: {
          bidderB: {
            pmp: {
              deals: [{ id:"dealB" }]     // apply this deal to bidderB
            }
          }
        }
      }
  }]
}

Custom Targeting

An OpenRTB extension, whether in the the original request or the stored-request, can customize the ad server targeting generated by PBS.

The OpenRTB field is ext.prebid.adservertargeting. Here’s an example:

"ext.prebid.adservertargeting":  [
  {
    "key": "hb_amp_ow",           // the targeting key
    "source": "bidrequest",       // pull the value from the path specified in the bid request object
    "value": "ext.prebid.amp.data.ow"  // path to value in the bidrequest
  },{
    "key": "hb_static_thing",
    "source": "static",          // just use the 'value' provided
    "value": "my-static-value"
  },{
    "key": "{{BIDDER}}_custom1", // {{BIDDER}} is a macro to be resolved
    "source": "bidresponse",     // pull the value from the path specified in the bid response object
    "value": "seatbid.bid.ext.custom1"
  }
]

ext.prebid.adservertargeting is an array objects. Each object has the following format:

In order to pull AMP parameters out into targeting, Prebid Server places AMP query string parameters in ext.prebid.amp.data. e.g.

"ext": {
  "prebid": {
    "amp": {
      "data": {
        "adc": "GA1.2.662776284.1602172186",
        "curl": "https://example.com/index.html",
        "debug": "1",
        "pvid": "",  // page view ID
        "ms": "",    // multi-size
        "ow": "",    // override-width
        "oh": "",    // override-height
        "w": "300",
        "h": "50",
        "gdpr_consent": "",
        "purl": "https://example.com/index.html",
        "slot": "/11111/amp_test",
        "timeout": "1000",
        "targeting": "{\"site\":{\"attr\":\"val\"}}",
        "tag_id": "amp-AMP_Test-300x250",
        "account": "22222"
      }
    }
  }
}

MultiBid

Allows a single bidder to bid more than once into an auction and have extra bids passed back to the client.

See the Prebid.js MultiBid Module for background information and use cases.

The Prebid extension to the OpenRTB protocol is ext.prebid.multibid. For example:

{
  "ext": {
    "prebid": {
      "multibid": [{
        "bidder": "bidderA",
        "maxbids": 2,
        "targetbiddercodeprefix": "bidA"
      }, {
        "bidder": "bidderB",
        "maxbids": 3,
        "targetbiddercodeprefix": "bidB"
      }, {
        "bidders": ["bidderC", "bidderD"],
        "maxbids": 2
      }]
    }
  }
}

MultiBid parameter details:

Prebid Server core does the following when it sees ext.prebid.multibid:

1. Before sending the request to bid adapters, it removes all entries from the multibid array except the one for that particular bid adapter. This lets the bid adapters be aware of how many bids they’re going to be allowed to submit into the auction.
2. Lets any additional bids through the OpenRTB response on seatbid[].bid[].
3. Adds the additional specified targeting on seatbid[].bid[].ext.prebid.targeting and repeats the biddercode used for targeting on seatbid[].bid[].ext.prebid.targetbiddercode.

Here’s an example response:

{
  "seatbid": [{
    "seat": "bidderA",
    "bid": [{
      "id": "bid1",
      "impid": "imp1",
      "price": 1.04,
      "ext": {
        "prebid": {
          "targeting": {
            "hb_pb_bidderA": 1.00
          },
          "targetbiddercode": "bidderA"
        }
      }
      ...
    }, {
      "id": "bid2",
      "impid": "imp1", // same imp as above
      "price": 0.8,
      "ext": {
        "prebid": {
          "targeting": {
            "hb_pb_bidA2": 0.50
          },
          "targetbiddercode": "bidA2"
        }
      }
      ...
    }]
  }]
}

Echo StoredRequest Video Attributes

Several video specific fields can be set in the Stored Request that the device player would not have context to at time of render. The requester (e.g. Prebid SDK) can send this signal to Prebid Server, which causes PBS-core to place the video-related attributes on the response.

{
  ...
  "imp": [{
    "id": "123456789",
    "video": {
      ...
    },
    "ext": {
      "prebid": {
        "storedrequest": {
          "id": "xxx"
        },
        "options": {
          "echovideoattrs": true
        }
      }
    },
    ...
  }]
  ...
}

1. Prebid Server receives this request and expands the storedrequest value, merging it with the imp object.
2. Because echovideoattrs is true, video parameters in the storedrequest imp[].video are copied to seatbid.bid.ext.prebid.storedrequestattributes.

{
  "seatbid": [{
    "bid": [{
      ...
      "ext": {
        "prebid": {
          "storedrequestattributes": {
            "maxduration": 60,
            "mimes": ["video/mp4"],
            "minduration": 15,
            "protocols": [1, 2],
            "skipafter": 0,
            "skipmin": 0,
            "startdelay": 0,
            "playbackmethod": [1]
          }
        }
      }
    }]
  }],
  ...
}

Request Passthrough

In support of the Prebid SDK, PBS supports a simple passthrough mechanism at two levels:

If the bidrequest contains a global $.ext.prebid.passthrough object, the object is copied to the bidresponse $.ext.prebid.passthrough with no validation other than it being valid JSON.

If the bidrequest contains impression-level $.imp[].ext.prebid.passthrough object, that object is copied to the bidresponse $.seatbid.bid.ext.prebid.passthrough with no validation other than it being valid JSON.

The initial use is for the SDK to define render-time parameters, but this mechanism may find use in other applications.

Floors

See the Prebid Server Floors Feature for more info.

Server Metadata

PBS-core creates this block before sending to bid adapters. They receive additional metadata about the PBS calling them. e.g.

"server": {
  "externalurl": "https://prebid-server.rubiconproject.com",
  "gvlid": 52,
  "datacenter": "us-east-1"
}

Analytics Extensions

Analytics adapter flags

Some analytics adapters may support special flags that can be passed on ext.prebid.analytics. e.g.

ext.prebid: {
  analytics: {
    myanalyticsadapter: {
      myflag: true
    }
  }
}

Sending analytics tags to the client-side

PBS-Java only

Analytics Tags (aka “aTags”) are an advanced feature that some modules and features utilize to communicate auction details to server-side analytics adapters.

When there are Prebid.js-based analytics adapters in use, server-side details can be sent to them with aTags. This allows the client-side analytics systems to see what’s happening within Prebid Server - all analytics tags created by all modules will be sent to the client.

To allow the sharing of these details, there are two conditions:

1. Server-side account configuration must allow sharing of these details by setting analytics.allow-client-details: true
2. The ORTB request must contain ext.prebid.analytics.options.enableclientdetails: true

If both are true, then any and all PBS analytics tags will be copied to the response field ext.prebid.analytics.tags.

See the Analytics Tags page for more information.

Preferred Media Type

PBS-Java only

This feature can be useful when a bid adapter either chokes on multiformat request, or if it makes a sub-optimal choice about which of multiple formats to consider. The publisher may be able to override bidder behavior from the request by passing in ext.prebid.biddercontrols.BIDDERCODE.prefmtype. The value must be “banner”, “video”, or “native”.

For example:

ext.prebid.biddercontrols: {
     "bidderB": { "prefmtype": "video" },
     "bidderC": { "prefmtype": "native" }
}

Here’s how this works:

1. If the bid adapter YAML declares support of multiformat, then prefmtype is ignored in the request. The default value of multiformat supported is true.
2. If the bidder declares that they don’t support multiformat and the incoming request contains multiple formats, then one of the formats is chosen by either $.ext.prebid.biddercontrols.BIDDER.prefmtype or config auction.preferredmediatype.BIDDER

OpenRTB Response Extensions

Bidder Response Times

response.ext.responsetimemillis.{bidderName} tells how long each bidder took to respond. These can help quantify the performance impact of “the slowest bidder.”

Bidder Errors

response.ext.errors.{bidderName} contains messages which describe why a request may be “suboptimal”. For example, suppose a banner and a video impression are offered to a bidder which only supports banner.

In cases like these, the bidder can ignore the video impression and bid on the banner one. However, the publisher can improve performance by only offering impressions which the bidder supports.

For example, a request may return this in response.ext

{
  "ext": {
    "errors": {
      "appnexus": [{
        "code": 2,
        "message": "A hybrid Banner/Audio Imp was offered, but Appnexus doesn't support Audio."
      }],
      "rubicon": [{
        "code": 1,
        "message": "The request exceeded the timeout allocated"
      }]
    }
  }
}

The codes currently defined are:

0   NoErrorCode
1   TimeoutCode
2   BadInputCode
3   BadServerResponseCode
999 UnknownErrorCode

Ad Server Targeting

Prebid Server will generate ad server targeting variables as defined by request parameters:

1. If ext.prebid.targeting.includewinners is true, seatbid.bid.ext.prebid.targeting will be defined for the top bid in each imp object and will carry the following targeting values: hb_pb, hb_size, and hb_bidder.
2. If ext.prebid.targeting.includebidderkeys is true, seatbid.bid.ext.prebid.targeting will be defined for the top bid from each bidder in each imp object and will carry the following targeting values: hb_pb_BIDDER and hb_size_BIDDER.
3. If ext.prebid.cache.bids is specified, any targeting objects will also contain hb_cache_id, hb_cache_id_BIDDER, hb_cache_host, and hb_cache_path.
4. If ext.prebid.cache.vastxml is specified, any targeting objects will also contain hb_uuid, hb_uuid_BIDDER, hb_cache_host, and hb_cache_path.
5. If the bid response defines a deal, any targeting objects will also contain hb_deal or hb_deal_BIDDER
6. If the request contains an app object, targeting objects will contain hb_env:mobile-app.
7. If the request is for the /amp endpoint, targeting objects will contain hb_env:amp. (PBS-Java 3.12+)
8. If ext.prebid.adservertargeting is defined, arbitrary targeting values may be specified.

{
  "seatbid": [{
    "seat": "bidderA",
    "bid": [{
      "id": "bid1",
      "impid": "imp1",
      "price": 1.04,
      "ext": {
        "prebid": {
          "targeting": {
            "hb_pb": 1.00, // values without prefixes on the winning bids only
            "hb_pb_bidderA": 1.00, // only if includebidderkeys is true
            "hb_bidder": "bidderA",
            "hb_size": "300x250",
            "hb_size_bidderA": "300x250",
            "hb_format": "video", // only if includeformat is specified
            "hb_deal": "123"      // only if bid response contains a deal
          }
        }
      }
      ...
    }]
  }]
}

Debug Output

response.ext.debug.httpcalls.{bidder} will be populated only if test:1 or ext.prebid.debug:true.

This contains info about every request and response sent by the bidder to its server. It is only returned on test bids for performance reasons, but may be useful during debugging.

response.ext.debug.resolvedrequest will be populated only if request.test was set to 1.

This contains the request after the resolution of stored requests and implicit information (e.g. site domain, device user agent).

"ext": {
  "debug": {
    "httpcalls": {
      "bidderA": [ ... ]
    },
    "resolvedrequest": { ... },
    "responsetimemillis": { ... }
    ...
  }
}

Original Bid CPM

response.seatbid[].bid[].ext.origbidcpm and response.seatbid[].bid[].ext.origbidcur will contain the original bid price/currency from the bidder. The value in seatbid[].bid[].price may be converted for currency and adjusted with a bid adjustment factor.

Seat Non-Bid

Prebid Server supports the Seat Non-Bid OpenRTB Extension that allows callers to get more information about bidders that had a chance to bid but did not. Eventually the system will support a fine-grained set of codes describing why a given bidder didn’t bid on a particular impression, but for now we’re phasing in the necessary internal infrastructure.

To enable the additional output, set ext.prebid.returnallbidstatus: true.

Here’s a sample response:

{ 
  ...
  "ext": {
    "seatnonbid": [
      {
        "seat": "someBidder",
        "nonbid": [
          {
            "impid": "test-div",
            "statuscode": 0
          }
        ]
      }
    ]
  }
}

The codes currently returned:

See the IAB’s Seat Non-Bid OpenRTB Extension for the full list of status codes that may be supported in the future.

OpenRTB Ambiguities

This section describes the ways in which Prebid Server implements OpenRTB spec ambiguous parts.

• request.cur: If request.cur is not specified in the bid request, Prebid Server will consider it as being USD whereas OpenRTB spec doesn’t mention any default currency for bid request. request.cur: ['USD'] // Default value if not set

OpenRTB Differences

This section describes the ways in which Prebid Server breaks the OpenRTB spec.

Allowed Bidders

Prebid Server returns a 400 on requests which define wseat or bseat. We may add support for these in the future, if there’s compelling need.

Instead, an impression is only offered to a bidder if bidrequest.imp[i].ext.{bidderName} exists.

This supports publishers who want to sell different impressions to different bidders.

Deprecated Properties

This endpoint returns a 400 if the request contains deprecated properties (e.g. imp.wmin, imp.hmax).

The error message in the response describes how to alter the request to make it acceptable for Prebid Server.

Determining Bid Security (http/https)

In the OpenRTB spec, request.imp[i].secure says:

Flag to indicate if the impression requires secure HTTPS URL creative assets and markup, where 0 = non-secure, 1 = secure. If omitted, the secure state is unknown, but non-secure HTTP support can be assumed.

In Prebid Server, an https request which does not define secure will be forwarded to Bidders with a 1. Publishers who run https sites and want insecure ads can still set this to 0 explicitly.

HTTP Headers

In order to facilitate compatibility and analytics, Prebid Server will add the x-prebid HTTP header to outgoing requests. Some examples:

x-prebid: pbs-go/0.155
x-prebid: pbjs/4.39,pbs-go/0.155
x-prebid: prebid-mobile/1.2.3,pbs-java/1.64

The PBJS version comes from ext.prebid.channel: {name: "pbjs", version: "4.39"}

The Prebid SDK version comes from:

"app.ext.prebid": {
   "source":  "prebid-mobile"
   "version": "1.2.3"
}

Prebid Server ORTB2 Extension Summary

Request

Response

Further Reading

• Example auction request
• OpenRTB 2.4 Specification
• OpenRTB 2.5 Specification
• OpenRTB 2.6 Specification