Ad Platform Glossary
Purpose
This document provides short, consistent definitions for the core terms that appear throughout the handbook.
Terms
Publisher
The party that owns the inventory where ads are shown and monetized.
SSP
The supply-side platform that orchestrates auctions for publisher inventory.
DSP
The demand-side platform that bids on ad opportunities on behalf of advertisers.
Exchange
The marketplace layer where supply and demand meet in real time. In practice, it may be distinct from or overlap with SSP behavior.
Ad Request
The runtime request sent by the publisher-side execution layer for a specific ad slot.
Bid Request
The auction request sent by an SSP or exchange to bidders. In OpenRTB contexts, this is the request that starts the bidding process.
Placement
The publisher-defined ad slot or inventory position.
imp
The OpenRTB object that describes an individual ad opportunity. It is different from the runtime impression event.
adm
The response field that carries creative markup or a renderable creative reference after the auction.
Audience Taxonomy
A consistent classification system for audiences or interests. In OpenRTB, segment IDs in user.data[].segment[] are typically interpreted as nodes in that taxonomy.
user.data
The OpenRTB array structure used to carry additional user or audience-related data.
segment
The child object inside an OpenRTB Data object that represents audience, interest, or provider-defined classification values.
VAST
The XML-based standard commonly used for video ad delivery and tracking.
Impression
The counting unit that represents an ad being shown or becoming eligible to be shown.
Viewability
The verification layer that checks whether an impression was meaningfully visible to the user.
Quartile
The video progress event family typically tied to 25%, 50%, 75%, and 100% playback milestones.
Discrepancy
A count difference between systems.
Reconciliation
The process of analyzing and resolving those count differences into an operational basis.
sellers.json
The IAB Tech Lab standard that exposes seller identity.
schain
The supply-chain object that explains how a bid request traveled through the supply path.