Real-Time Bidding
An auction-based mechanism where individual ad impressions are bought and sold in real time as a user loads a page, with the entire bidding process completing in under 100 milliseconds per impression.
Real-time bidding (RTB) is the transactional protocol that powers most programmatic advertising. When a user visits a page, an ad request triggers an auction where multiple advertisers submit bids for that specific impression. The auction completes before the page finishes loading, and the winning ad is displayed to the user.
RTB is where AI and growth engineering intersect most directly in adtech. Each bid decision is essentially a prediction problem: given what we know about this user, this context, and this placement, what is the expected value of showing our ad? Growth teams that build custom bidding models or leverage DSP machine learning features can significantly outperform competitors using static bid strategies. The key engineering challenge is latency, as bid responses must arrive within strict time limits, requiring optimized inference pipelines and efficient feature stores. Teams that master RTB optimization gain a structural advantage in paid acquisition efficiency.
Related Terms
Programmatic Advertising
The automated buying and selling of digital ad inventory using software platforms and algorithms, replacing manual negotiation with real-time, data-driven decision-making across display, video, and native channels.
Demand-Side Platform
A software platform that enables advertisers and agencies to purchase digital ad inventory across multiple ad exchanges through a single interface, using data and algorithms to optimize bidding and targeting decisions.
Supply-Side Platform
A technology platform used by publishers and app developers to manage, sell, and optimize their advertising inventory across multiple demand sources, maximizing revenue per impression through automated auction mechanics.
Ad Exchange
A digital marketplace that facilitates the buying and selling of advertising inventory between advertisers and publishers in real time, operating as a neutral auction platform connecting DSPs and SSPs.
Header Bidding
A programmatic technique where publishers simultaneously offer ad inventory to multiple demand sources before calling their primary ad server, increasing competition and revenue by allowing all bidders to compete on equal footing.
Cost Per Mille
The cost an advertiser pays for one thousand ad impressions served, commonly abbreviated as CPM. It is the standard pricing unit for display and video advertising across programmatic and direct buying channels.