An ad network sits between two groups that rarely deal with each other directly: advertisers who want to reach users, and publishers who have app inventory to sell. The network aggregates unsold inventory from many publishers, gathers demand from many advertisers, and matches the two so ads fill available placements. For a mobile publisher, a network is often the first demand source added after launch, because it removes the need to negotiate with advertisers one at a time.

How it works

A publisher integrates the network's SDK or connects through a mediation layer, then exposes ad placements the network can fill. The network holds a pool of advertiser demand and decides which ad to serve each time a placement requests one, usually by maximizing the price it can pay while respecting advertiser targeting and budgets. Publishers are paid on the underlying pricing model the network runs, often CPM, CPC, or CPA, and they track the result as eCPM so they can compare the network against every other source.

Ad network vs. ad exchange

The two are easy to confuse. An ad network aggregates and often curates inventory, then sells it in packages at prices it sets or negotiates. An Ad Exchange is an open, real-time auction where many buyers bid on each impression as it becomes available. A network feels more like a managed storefront, while an exchange feels like a live marketplace. Networks can offer curation and account support, and exchanges tend to offer scale and price discovery. Most publishers end up using both.

Why publishers work with several networks

No single network has demand for every impression in every country at every moment. When one network has no suitable advertiser, the placement goes unfilled and earns nothing, which drags down Fill Rate. Running several networks through an Ad Mediation layer lets a publisher fall back from one to the next, so more impressions sell and competition between networks pushes prices up. The trade-off is added SDK weight and more relationships to manage, so publishers weigh each network's contribution before keeping it in the stack.

Where offerwalls fit

An offerwall is a specialized demand source rather than a general one. Instead of serving passive banner or video impressions, it presents users with a menu of offers they can complete for a reward, and it pays on completed actions. Because that demand is engagement-based and high-intent, an offerwall placement can post a higher eCPM than generic network demand for the same audience. Publishers usually run an offerwall alongside their networks rather than in place of them, treating it as a distinct rewarded revenue stream that fills a slot standard networks cannot.

Common mistakes to avoid

• Judging a network by its headline eCPM alone. A high eCPM on a source that rarely fills earns less than a steady source with moderate prices.

• Stacking too many networks. Each SDK adds weight and maintenance, and low-contributing networks can slow the app without adding real revenue.

• Ignoring how networks overlap. Two networks may be buying the same demand, so adding the second one lifts costs without lifting fill.