In-app reaches users inside mobile applications rather than mobile web — where most mobile time is actually spent.
Why it's distinct
- Attention — app sessions are focused and intentional in a way mobile browsing often isn't.
- Identifiers — apps provide device-level identifiers, making attribution more reliable than cookie-based mobile web.
- Context — the app itself signals interest. A user in a fitness app tells you something a random mobile page doesn't.
- Ad-blocker resistant — in-app inventory is largely unaffected by browser ad blocking.
Formats available in-app: display, native and video.
Supply
Mobile inventory providers cover both in-app and web environments — see Who are the supply partners and how is this different from standard access?.
Verification
app-ads.txt verification confirms a seller is authorised to sell an app's inventory — the app-side equivalent of ads.txt, and an important check because app inventory has historically attracted more spoofing. See Are industry and privacy standards supported?.
Measurement: mobile attribution platforms are available through the plugin library and integrations — see Can the platform integrate with third-party systems?. Set attribution up before scaling; in-app attribution is harder to reconstruct after the fact than web.
Related: How does native advertising improve engagement? · Is fraud detection and prevention included?