How Web, App, and CTV Differ

Purpose

This document explains the practical differences between web, app, and CTV environments in ad platform design. Even when the same standards are involved, runtime behavior, measurement, and creative delivery differ by channel.

Key Takeaways

Web is centered on browsers and tag or script execution.
App is centered on SDK-driven runtime behavior and bundle-based identity.
CTV is app-based, but player-driven video execution and household device context matter more.
The same request concept can lead to different identifiers, renderers, and event rules across channels.

Channel Comparison

Dimension	Web	App	CTV
Runtime owner	Browser, tag, script	App SDK, mediation SDK	TV app, player SDK
Context object	`site`	`app`	Mostly `app`
Identity basis	Domain, page URL	Bundle, store URL	Bundle, app/store, device context
Common formats	Display, video	Display, rewarded, interstitial, video	Mostly video
Measurement emphasis	Browser constraints, privacy limits	SDK event collection	Player events, quartiles, completion

1. Web

Domain and page URL are key context signals.
Ad tags, header bidding scripts, and player scripts often initiate runtime requests.
Browser policies and privacy restrictions affect execution and identity.

2. App

The SDK is usually the main runtime owner for request, render, and tracking behavior.
bundle, storeurl, and app-ads.txt matter more than page-level context.
Rewarded, interstitial, and in-app video formats appear more often.

3. CTV

Technically close to app, but operationally much closer to a video and player environment.
The player becomes the main owner of quartiles, completion, and playback state.
Household or shared-device assumptions often differ from mobile app assumptions.

Implementation Notes

The same event name may not mean exactly the same thing across channels.
It helps to separate channel, runtime, player_type, and sdk_type early in schema design.