How large is a typical bid request and what volume should I expect?
Answer
There is no fixed size: a bid request is usually a few kilobytes of JSON, growing with eids arrays, supply chains, and multi-format impressions, and the spec does not set a limit. Volume depends entirely on how much of an exchange's traffic you take; production DSP endpoints commonly handle very large request rates, which is why the spec's stated best practices are gzip compression (negotiated via Accept-Encoding) and HTTP persistent connections to cut connection overhead. Whatever the volume, each response must arrive within tmax, which includes network latency in both directions.
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.