The data payloads are described in Section 3 and Section 4.
Optionally, an exchange may also offer binary representations (e.g., compressed JSON, ProtoBuf, Avro, etc.), which can be more efficient in terms of transmission time and bandwidth. The IAB Tech Lab may offer reference implementations for these or other formats. When available, the use of these IAB reference implementations is highly recommended to reduce exchange-specific variations.
The bid request specifies the representation as a mime type using the Content-Type HTTP header. The mime type for the standard JSON representation is “application/json” as shown. The format of the bid response must be the same as the bid request.
If alternative binary representations are used, the exchange or SSP should specify the Content-Type appropriately. For example: “Content-Type: avro/binary” or “Content-Type: application/x-protobuf”. If the content-type is missing, the bidder should assume the type is application/json, unless a different default has been selected by an exchange.
As a convention, the absence of an attribute has a formal meaning. In most cases, this indicates that the value is unknown, unless otherwise specified.
XML is a file extension for an Extensible Markup Language (XML) file format used to create common information formats and share both the format and the data on the World Wide Web, intranets, and elsewhere using standard ASCII text. XML is similar to HTML.
VAST is a specification defined and released by the Interactive Advertising Bureau that sets a standard for communication requirements between ad servers and video players in order to present video ads. It is a data structure declared using XML.
VPAID stands for Video Player-Ad Interface Definition. VPAID is a common interface between video players and ad units, enabling a rich interactive in-stream ad experience.