To clearly understand what is an ad tech stack, it helps to see it as a coordinated ecosystem of ad tech tools that automate how digital ads are bought, sold, delivered, and measured.
Each layer of the ad tech stack plays a distinct role, but real value appears when they work together.
For Advertisers (Demand Side)✦ Demand-Side Platforms (DSPs)
DSPs allow advertisers to buy ad inventory across thousands of websites and apps in real time. Using data and bidding logic, DSPs decide which ad to show, to whom, and at what price.
✦ Advertiser Ad Servers Ad Servers host creatives, track impressions, clicks, and conversions, enforce frequency capping, and provide independent measurement across platforms. They ensure consistency and transparency when campaigns run across multiple DSPs and publishers.
✦ Data Management Platforms (DMPs and CDPs)
These Ad Tech tools collect, structure, and activate audience data. They help advertisers build segments using first and third party data, a critical function as third-party cookies continue to disappear.
For Publishers (Supply Side)✦ Supply-Side Platforms (SSPs)
SSPs help publishers sell their ad inventory efficiently by exposing it to multiple DSPs and exchanges, maximizing yield through real-time auctions.
✦ Publisher Ad ServersThese platforms manage ad delivery on publisher-owned properties, enforce rules like frequency capping, and ensure ads are rendered correctly.
The Marketplace Layer✦ Ad ExchangesAd exchanges are real-time marketplaces connecting DSPs and SSPs. They enable automated buying and selling of impressions at massive scale within milliseconds.
Supporting Ad Tech Tools✦ Ad Networks — aggregate inventory and resell it to advertisers
✦ Analytics and Measurement Platforms — attribution, brand lift, ROI analysis
✦ Creative Management Platforms (CMPs) — build, test, and optimize ad creatives
In simple terms, an ad tech stack works like a layered factory where data platforms define audiences, DSPs bid for impressions, SSPs offer inventory, and analytics tools measure results, all automated for speed and scale.