Glossary
What is ad tech?
Ad tech is the ecosystem of software, tools and platforms used to plan, execute, deliver and measure digital advertising — everything between an advertiser's budget and a user's screen.
The layers
- Demand. DSPs, ad networks and buying tools.
- Supply. SSPs, mediation and publisher yield tools.
- Exchange. The marketplaces where the two meet.
- Serving. Ad servers that store creative, decide what to return, and log it.
- Measurement. Attribution, verification, MMPs and analytics.
- Data. Audience platforms, clean rooms and identity resolution.
Why the stack is as complicated as it is
Not by design. Each layer solved a real problem at the moment it appeared — exchanges solved liquidity, SSPs solved publisher control, verification solved fraud and viewability, identity vendors solved fragmentation — and nothing was ever removed.
The result is a supply chain where a meaningful share of every pound is consumed before reaching a publisher, and where a single impression can pass through six systems each logging it slightly differently. Most disagreements between reports in digital advertising trace back to that.
What the current shift changes
Two structural pressures are reshaping the stack simultaneously.
Identity loss removed the assumption the audience-targeting layer was built on, pushing value back toward context and toward first-party data.
Conversational surfaces break the page abstraction the whole stack encodes: no URL, no slot, no size, and a latency budget that sits inside response generation rather than page load.
The result is not a replacement stack but a parallel one — AI DSPs, AI SSPs, protocols such as AdCP — built for inventory the existing pipes cannot describe. Our ad tech landscape page maps where the pieces currently sit.
Common questions
Is ad tech the same as martech?
Overlapping and distinct. Ad tech buys and delivers paid media; martech manages owned relationships — CRM, email, automation. Customer data platforms sit in between and are claimed by both.
Is the ad tech stack getting simpler?
Consolidating in places and fragmenting in others. Identity loss has removed some layers; conversational surfaces are adding new ones.
Where we write about ad tech
More in programmatic and supply
The exchanges, platforms and inventory an impression passes through.