What format and encoding rules apply to OpenRTB payloads?
Answer
OpenRTB payloads are JSON sent over HTTP POST with Content-Type application/json, and the response must use the same representation as the request. Standard JSON rules apply: no comments, no trailing commas, string keys in double quotes; hand-edited requests with comment lines are a frequent cause of HTTP 400 rejections. The spec gives the absence of an attribute formal meaning, usually that the value is unknown, so omit fields rather than sending null. Exchanges may agree on binary alternatives like Protobuf or Avro with an appropriate Content-Type, and gzip compression is a documented best practice.
Go deeper
More questions on openrtb basics and the bid request
- What is OpenRTB? OpenRTB is the IAB Tech Lab standard that defines the JSON messages ad exchanges and bidders use to buy and sell impressions in real time.
- How does a real-time bidding auction work end to end? A user loads a page or app, the publisher's ad system asks an exchange to sell the impression, and the exchange sends an OpenRTB BidRequest over HTTP POST to many bidders at once.
- What's the difference between OpenRTB and Prebid.js? OpenRTB is a wire protocol; Prebid.js is a piece of software.
- Is header bidding the same as OpenRTB? No.
- What's the difference between an SSP, a DSP, and an ad exchange? From the protocol's point of view there are only two roles: the supply side sends OpenRTB bid requests and runs the auction, and the demand side receives them and bids.
- What is a bid request in programmatic advertising? A bid request is the JSON message an exchange sends to bidders to offer one or more impressions for sale.
All 93 questions are listed in the OpenRTB FAQ.