Glossary
What is Ad exchange?
Also called: exchange, AdX
An ad exchange is a marketplace that runs an auction for each impression, letting many buyers bid on many publishers' inventory.
हिंदी में पढ़ेंThe IAB Tech Lab’s OpenRTB specification describes an exchange as a service that conducts an auction among bidders per impression. Sellers offer impressions through it, buyers’ platforms send bids, and the exchange picks the winner under its auction rules. Most programmatic exchanges now run first-price auctions, where the winner pays what it bid.
An exchange differs from an ad network. A network gathers ad space from many sites and resells it to its own advertisers, taking a cut. An exchange is an open marketplace where many buyers and sellers meet. In practice an SSP and an exchange are often the same company, so the two words are frequently used together.
Google’s exchange is Google Ad Exchange (AdX), reached through Google Ad Manager, with publisher controls such as floors and private deals. Inside Ad Manager it competes at priority 12, and through dynamic allocation it can also compete with guaranteed line items.
Example
One impression goes to an exchange. Three buyers bid CPMs of $1.80, $2.10 and $2.40. In a first-price auction the $2.40 bid wins and pays $2.40, about $0.0024 for that single impression before fees.
Why it matters to publishers
Exchanges are where much of the open-market demand reaches your pages. Knowing which ones see your inventory, and through which paths, helps you understand who your buyers are and what each hop costs.