Glossary
What is Ad server?
Also called: publisher ad server
An ad server is the software that decides which ad fills each slot, applying the publisher's rules for priority, targeting and price.
हिंदी में पढ़ेंAn ad server is the referee for your ad slots. When a page sends an ad request, the ad server looks at every source of demand that could fill it, such as direct campaigns, header bids, exchanges and house ads. It checks each one against your rules, like priorities, targeting and minimum prices, and picks the winner. Google Ad Manager is the best-known publisher ad server.
An ad server is not an SSP. An SSP finds outside buyers and runs its own auction; the ad server decides between everything that reaches it. In a standard Prebid setup, header bids arrive at the ad server as key-values, and the ad server makes the final decision.
Google Ad Manager blurs the line, because it bundles an ad server with Google’s ad exchange, AdX. Inside it, campaigns are stored as orders, line items and creatives.
Example
A slot gets three offers: a direct campaign that has already hit its goal, a header bid at a $2.50 CPM and an AdX bid at $2.20. The ad server sets the direct campaign aside and serves the $2.50 header bid.
Why it matters to publishers
The ad server holds your rules, so many yield problems, from wrong priorities to missing line items, are fixed there. Knowing its job helps you see which vendor does what.