bidrequest

A bid request is a data message used in programmatic advertising to solicit bids for a single ad impression. It is generated when a publisher’s ad system identifies an available inventory opportunity and is sent to potential buyers, such as demand-side platforms (DSPs) or ad exchanges, through real-time bidding protocols.

A bid request typically follows a standard such as OpenRTB and includes an impressions array. For each impression, fields describe the ad slot (size, position, and bid floor), along with contextual information such as the publisher or app domain, site or app category, and device details (type, OS, language, user agent). It may also carry anonymized user identifiers, geographic hints, and interest or audience data when available. Privacy-related data, including consent strings compliant with regulations like GDPR or CCPA, may be included or referenced in the request.

The bid request travels from the publisher or its supply-side platform (SSP) to participating bidders, often via an ad exchange or header bidding setup. Demand-side platforms respond with bid responses that contain bid price, a proposed creative, and related identifiers. The ad exchange or waterfall mechanism then selects a winner based on price and other criteria, and the winning bid is returned to the publisher for ad delivery.

Privacy, data governance, and compliance are important considerations in bid requests. Publishers and buyers manage consent, data minimization, and regulatory requirements, which can influence which data fields are transmitted. The size and content of bid requests can affect latency, so standards and optimization practices aim to balance data richness with performance.