# Ad exchange

Concept · [Business and metrics](https://ecosystem.samcarlton.com/business)

Also called: ad exchanges, ad marketplace

The digital marketplace where ad space from sellers is auctioned to advertisers in real time.

**For example:** An ad exchange matches a site's open ad slot with bids from several advertisers' platforms in milliseconds.

## Connects to (4)

- [Programmatic advertising](https://ecosystem.samcarlton.com/programmatic-advertising): Buying and selling online ad space automatically through software, often in auctions that run in a fraction of a second as a page loads.
- [Demand-side platform](https://ecosystem.samcarlton.com/demand-side-platform): Software that advertisers use to buy ad space across many websites and apps automatically, with targeting and budget rules.
- [Supply-side platform](https://ecosystem.samcarlton.com/supply-side-platform): Software that websites and apps use to sell their ad space automatically to many buyers at once.
- [CPM](https://ecosystem.samcarlton.com/cpm): Cost per thousand impressions.

Map view: https://ecosystem.samcarlton.com/ad-exchange