Explore ads.txt, app-ads.txt, sellers.json, OpenRTB, VAST, VMAP, supply chain and CMP — important concepts used across the digital advertising ecosystem.
Programmatic advertising involves many platforms, companies and technologies. These standards help different parts of the ecosystem communicate, verify relationships and manage advertising transactions.
A publisher may work with multiple SSPs, exchanges, ad servers and other technology providers while advertisers and DSPs evaluate inventory through automated buying systems.
Standards such as ads.txt, sellers.json and OpenRTB help different parts of this ecosystem work together with greater transparency.
Authorized digital sellers for publisher inventory.
ads.txt is a text file that publishers place on their website to identify the advertising platforms and seller accounts that are authorized to sell their ad inventory.
Buyers and advertising platforms can use the information in ads.txt as one of the checks when evaluating whether inventory is being sold through an authorized seller.
google.com, pub-1234, DIRECT, f08c47fec0942fa0
ads.txt tells buyers which advertising platforms and seller accounts a publisher authorizes to sell its inventory.
Authorized sellers for app advertising inventory.
app-ads.txt follows the same basic authorization concept as ads.txt, but it is designed for advertising inventory associated with mobile applications and other supported app environments.
App developers can publish an app-ads.txt file on their associated developer website so buyers can verify authorized sellers.
ads.txt → Website inventory
app-ads.txt → App inventory
Information about sellers and intermediaries in the advertising supply chain.
sellers.json provides information about organizations participating in the advertising supply chain.
It allows buyers to obtain information about sellers and intermediaries involved in selling inventory and understand who is represented by a particular seller ID.
{
"seller_id": "pub-1234",
"name": "Company Name",
"seller_type": "PUBLISHER",
"domain": "pubsrate.com",
"is_passthrough": false
}
ads.txt tells buyers which sellers a
publisher authorizes.
sellers.json helps buyers understand
who those sellers are.
A common protocol used for real-time programmatic bidding.
OpenRTB is a protocol used by advertising technology platforms to exchange information about an advertising opportunity and conduct automated bidding.
An ad request can contain information about the available inventory, such as the website or app, ad format, device and other applicable signals.
Buyers can use the available information to decide whether they want to participate and what they are willing to bid.
OpenRTB provides a common way for advertising platforms to communicate during a real-time programmatic auction.
Video ad serving communication between ad systems and video players.
VAST (Video Ad Serving Template) is an IAB standard used to communicate video advertising information between an ad server and a video player.
VAST is commonly delivered as an XML document containing information about the video advertisement, creative resources, tracking events and other instructions needed by the player.
VAST = Information that tells a video player how to handle a video advertisement.
A standard for describing advertising opportunities within video content.
VMAP (Video Multiple Ad Playlist) is an IAB standard used to describe where advertising breaks can occur within video content.
It can define opportunities such as pre-roll, mid-roll and post-roll advertising breaks.
VMAP = A structure that tells the video player where advertising breaks can occur.
They work together in video advertising, but they solve different problems.
| Area | VAST | VMAP |
|---|---|---|
| Main purpose | Communicates information about a video ad | Defines advertising break opportunities |
| Focus | Advertisement | Ad break structure |
| Example | Creative and tracking information | Pre-roll, mid-roll and post-roll positions |
The path an advertising opportunity can take through the programmatic ecosystem.
Managing privacy and consent choices.
CMP (Consent Management Platform) is a technology used by websites and apps to collect and manage a user's privacy and consent choices.
A CMP can present users with information about different purposes of data processing and allow them to make choices about what they consent to.
The resulting consent information can then be communicated to participating advertising and technology partners.
CMP = A system that helps websites and apps collect and manage user consent choices.
These technologies solve different problems across the advertising ecosystem.
This page has been written and structured by PubsRate for educational and informational purposes. The explanations, examples, diagrams and presentation are created for the PubsRate platform.
Third-party standards, company names, trademarks, products and technologies mentioned on this page belong to their respective owners. Mentioning a technology or company does not imply endorsement or affiliation.
This content is intended to explain concepts in a simplified way. Technical implementations may differ between platforms and environments.
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Last reviewed: August 2026
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