Glossary/Programmatic/Ad server
What is an ad server and what does it do for publishers?
What an ad server does, the difference between publisher and advertiser ad servers, and how audience data fits in.
Written by Samhub with the help of AI·Updated 13 Oct 2026·3 min readAn ad server is the system that decides which ad to show in each ad slot, delivers it, and counts impressions, clicks and other results.
What an ad server does
Stores campaigns
Creatives, dates, targeting and goals.
Decides
Picks the best ad for each request.
Delivers
Sends the ad to the page.
Counts
Impressions, clicks and delivery.
Publisher vs advertiser ad servers
| Publisher ad server | Advertiser ad server | |
|---|---|---|
| Used by | Publishers | Advertisers and agencies |
| Manages | Inventory and campaigns on the site | Creatives and tracking across sites |
| Example | Google Ad Manager | Campaign Manager 360 |
16 pages for publishers, with a checklist for data, programmatic and direct sales.
Audience data in the ad server
When audiences are passed to the ad server as key values, direct campaigns can target them in the same setup sales teams already use.
CPM uplift at Stampen Media after activating first-party audiences with Samhub.
Frequently asked questions
No. The ad server decides between all demand; the SSP is one source of programmatic demand.
Google Ad Manager is the most common.
They count at different moments and filter traffic differently.
Giving one demand source the first chance to buy before others.
Related terms
Google’s ad server and exchange for publishers.
The team that sets up, runs and reports campaigns.
The software publishers use to sell impressions.
A space on a page where an ad can appear.
Setting campaigns up in the ad server.
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