TAG BASICS

Let’s talk
about tags.

Ad tags can look similar in a trafficking sheet while doing very different jobs. This visual guide explains what they carry, what they measure, and where they normally run.

Animated diagram: a publisher creates an ad opportunity, an ad tag requests creative and trackers from an ad server, the server returns media and tracking, and a user click opens a landing page. — How an ad request connects the creative, measurement, and landing page.

AD DELIVERY & AD-SIDE TRACKING

What runs with an ad

Banners, video, audio, and their 1×1 trackers travel with or measure an advertising experience.

WEBSITE ACTIVITY

What measures a site

Site tags and Floodlights observe visits, actions, and conversions on a brand’s website or landing page.

VERIFICATION

What validates delivery

IAS, DoubleVerify, and similar vendors measure signals such as viewability, fraud, suitability, and verification events.

INTEGRATIONS

What connects systems

APIs can support trafficking, reporting, asset management, measurement, or many other platform-to-platform uses.

DESTINATION — NOT A TAG TYPE

Landing pages: where clicks finish

A landing page is the destination a person reaches after selecting an ad. It is not an ad tag, but its URL is part of the campaign experience: click trackers may redirect to it, and its parameters can carry UTMs, attribution values, or other campaign information.

Ad click→Click tracker→Landing page

Check that the final domain is the intended destination
Confirm redirects preserve important UTM and tracking parameters
Remember that access restrictions, consent tools, or regional rules can affect what a visitor sees

Open Landing Page QA →

SERVING CONCEPT — NOT A TAG TYPE

Default ad / fallback creative

A default ad is the backup creative selected by the ad server when no other assigned ad is eligible to serve. It does not require a separate publisher tag.

1Placement tag requests an adThe same display or VAST placement tag is used.

2Is a regular ad eligible?The server evaluates dates, targeting, compatibility, and other settings.

YES Regular campaign ad servesNO Default ad serves as backup

Why TagCheck cannot detect it: the exported tag normally identifies the placement and calls the ad server. The default-ad assignment lives in the campaign configuration and is chosen at serve time, so it is usually not exposed in the pasted tag.

CM360 context: default ads can support matching display and in-stream placements. They have no targeting criteria and serve when no other ad is eligible. Without a usable fallback, display inventory may show blank space or a grey image, while video inventory may simply return to publisher content.

MEASUREMENT

1×1 tracking pixel

A tiny image request—often visually invisible—used to tell a server that an impression or event happened. The URL can carry campaign IDs, cachebusters, consent signals, and other macros.

Page or ad→Pixel URL→Event logged

Does not contain the main creative
May be an impression, verification, or research pixel
Can appear inside HTML, JavaScript, or VAST

VIDEO

VAST

VAST is an XML response that tells a video player what media to play and which events to track. It can include multiple renditions, duration, click-through URLs, quartile trackers, and wrapper URLs.

Start25%50%75%Complete

The player—not the XML itself—plays the video
Wrappers can point to another VAST response
MediaFile options let a player choose a compatible rendition

INTERACTIVE VIDEO

VPAID

VPAID adds executable creative code and interaction logic to video advertising. It was commonly delivered through VAST, but support has declined because of security, performance, and cross-device limitations.

VAST→VPAID code→Interactive ad

Can control playback and interactive behavior
May use JavaScript or legacy Flash assets
A “VPAID present” result is not a guarantee of player support

AUDIO

Audio ads & companion banners

An audio ad delivers a sound file to a compatible player, often through VAST. The same response can include a companion creative—usually an image or HTML banner displayed beside the player while the audio is playing.

♪Audio creative

CompanionImage or HTML

Audio can use start, quartile, complete, impression, and click trackers
Companions may have their own size, resource, click-through, and tracking URLs
A companion supports the audio experience; it is not the primary audio file

SITE MEASUREMENT

Site tags & Floodlights

A site tag runs on a webpage to measure visits, actions, or conversions. A CM360 Floodlight is one type of site-measurement request, identified by advertiser and activity values such as src, type, and cat.

LP visit→Page action→Floodlight

type is the activity-group string
cat is the activity string
Friendly names usually require access to the advertiser’s private CM360 configuration

VERIFICATION MEASUREMENT

IAS, DoubleVerify & verification tags

Verification technology measures how and where an ad was delivered. Vendors such as Integral Ad Science (IAS) and DoubleVerify can be included through JavaScript, pixels, VAST verification elements, wrappers, or server-to-server integrations.

Ad serves→Verification observes→Signals reported

ViewabilityInvalid trafficBrand suitabilityGeo/device

Presence in a tag shows that verification code or tracking was included
Some integrations are added at the platform or placement level and may not be explicit in the original tag
A static test can identify evidence, but final measurement depends on the live serving environment

SERVER CONNECTION

API integrations

An API is not usually a creative tag. It is a structured way for platforms or servers to exchange campaign data, assets, reporting, or event information. Server-to-server measurement can reduce the amount of visible code inside a tag.

Platform A⇄API⇄Platform B

Often uses authenticated requests and structured JSON
May create or retrieve tags rather than render them
Some integrations cannot be confirmed from tag text alone

Quick comparison

Format	Main job	Usually contains	Best TagCheck workflow
1×1 pixel	Measure an event	A tracking URL and parameters	Banner or video analysis
Banner	Render display creative	HTML, JavaScript, images, click tracking	Banner
VAST	Describe a video ad	XML, media files, events, clicks, wrappers	Video workflow matching the ad server
Audio	Deliver an audio ad	Audio files, events, clicks, optional companions	VAST/audio analysis
VPAID	Run interactive video code	Executable creative unit referenced by VAST	Video analysis + VPAID check
Floodlight/site tag	Measure site activity	Activity identifiers and event data	Detected inside submitted tags
Verification	Measure delivery quality	IAS, DoubleVerify, verification scripts, pixels, or events	Wrapper, pixel, script, and VAST checks
API	Exchange data server-to-server	Requests, responses, authentication, JSON	Not a paste-in creative format

Important: One ad can use several of these at once. For example, a VAST response can contain 1×1 impression trackers, a click-through URL, verification code, and multiple video files.

Let’s talkabout tags.