什麼是 app-ads.txt？

Authorized Sellers for Apps (或稱 app-ads.txt) 是授權數位賣方標準的擴充功能，可進一步相容支援要在行動應用程式中顯示的廣告，同時確保應用程式廣告空間只會透過您授權的管道出售。您可以藉由建立 app-ads.txt 檔案，更全面地控管誰可在您的應用程式上銷售廣告空間，以免廣告客戶誤向假冒的不肖分子購買廣告空間。

app-ads.txt 檔案會開放給廣告交易平台、供應端平台 (SSP) 和其他買方與第三方廠商使用及檢索。

什麼是 ads.txt？

適用於網站的授權數位賣方 (或稱 ads.txt) 是一項由 IAB 推動的計畫，目的是讓程式輔助廣告流程更透明。您可以自行建立 ads.txt 檔案，區分出有權銷售廣告空間的賣方。這些公開檔案可供廣告交易平台、供應端平台 (SSP)、其他買方和第三方供應商檢索。

您的 ads.txt/app-ads.txt 不可遭到地理圍欄封鎖。

How To Create And Post An Ads.Txt File

Definition: Publisher IDs

What are publisher IDs? Sometimes called the seller network id or the account id,

these are the IDs associated with a Publisher’s account on an exchange or SSP platform. Content owners, publishers and their reseller networks and other businesses may all have accounts on these platforms. As a best practice this ID is transmitted as part of the OpenRTB protocol as the Publisher.ID along with the Publisher.Domain in the Publisher object. In other RTB protocols this may be called ‘seller_network_id’, member or seat ID.

Domain owners

Domain owners will need to post their Publisher ID for every exchange where they have an account. Exchanges already pass a Publisher ID in every call, and it represents the account owner that is getting paid for the media sold from it. Since this is already in every bid request it should be easy for exchanges to provide these IDs to domain owners and networks selling on their exchange.

As a best practice, exchanges should make it easy for domain owners and third party resellers to access their Publisher ID’s for sharing. If an exchange has multiple Publisher.ID’s for a single domain – for example if they have one for a header integration, and another for the tag in the domain owner’s ad server – they will need to provide the domain owner with both ID’s for publication.

Third party sales houses and aggregating networks

Third party sales houses and aggregating networks need to make sure that they provide the full list of exchange-based Publisher ID’s that they use to sell inventory, so that the domain owner can publish that information in their ads.txt file. If the partner doesn’t give the domain owner the correct information to post in the ads.txt file, buyers may not view the inventory as authorized and may value it lower than through a more transparent channel.

How To Use Ads.Txt

Buying platforms

Buying platforms (e.g. DSP’s and Networks) can crawl the web to acquire the Authorized Digital Sellers list for every domain. This list will identify the Exchange or SSP that the domain is authorized to be sold on, and the Publisher ID on each exchange that is explicitly authorized to sell the domain. Additionally, ads.txt enables the buyer to determine if the Publisher ID that they are buying the domain from is owned and operated by the publisher, or if it is an authorized seller.

Ads.Txt Helps Publishers

Counterfeit inventory comes in many forms, but it typically results in real media spend not reaching legitimate and deserving publishers. Ads.txt helps publishers reclaim control of their media, brand, and rate card. This means more of an advertiser’s spend can get to the domain owner through their approved sales channels, and not be wasted on counterfeit inventory.

Ads.Txt Helps SSPs/Exchanges

SSP’s and Exchanges with direct relationships with domain owners can be harmed by the amount of counterfeit and misrepresented inventory in the market today because it is usually cheaper than the real thing, or outperforms the real media due to less accountable KPI’s. Buyers who generally target domains across multiple exchanges are attracted to the low prices and seemingly “high performance” of the same domain on exchanges that don’t have direct relationships with the domain owners themselves. Sometimes, this cheap and high performing inventory is not actually inventory on the domain that the buyer wanted, but is misrepresenting the domain, format or serving environment to manufacture lower prices and higher performance. This means buyers may end up directing more of their spend to counterfeit inventory than to legitimate publishers on their preferred SSPs and Exchanges partners, harming honest SSPs, Exchanges and Publishers bottom line.

Ads.Txt Helps Advertisers

By using buying platforms that support ads.txt, Advertisers can be more confident that their working media budget is going to accountable media, and not counterfeit inventory.

Programmatic buying has historically focused on URLs and domains relying on the assumption that they represent authentic inventory. This has left the door open to various types of invalid and fraudulent activities such as creating and selling counterfeit inventory. Ads.txt helps address this problem by giving buyers the choice to only buy from authorized digital sellers of a participating domain.

Ads.Txt Helps DSPs

DSPs that want to help their advertisers buy in a more secure fashion can now offer their Advertisers Authorized Digital Seller inventory. Ads.txt is not prescriptive about its use, so each DSP can form and create their own approach to advertisers to differentiate their offering from others.

Ads.Txt Helps Third Party Networks And Sales Houses

Many domain owners turn to others for help monetizing their inventory. That’s why Ads.txt is built to provide networks and sales houses with a way to differentiate themselves in the market and become authorized sellers of specific domains. With ads.txt, they can make sure that their value proposition or relationship with a domain owner is uniquely valued, and cannot be undercut by counterfeit inventory or other fraudulent behaviors.

What Is The Ads.Txt Project?

The mission of the ads.txt project is simple: Increase transparency in the programmatic advertising ecosystem. Ads.txt stands for Authorized Digital Sellers and is a simple, flexible and secure method that publishers and distributors can use to publicly declare the companies they authorize to sell their digital inventory.

By creating a public record of Authorized Digital Sellers, ads.txt will create greater transparency in the inventory supply chain, and give publishers control over their inventory in the market, making it harder for bad actors to profit from selling counterfeit inventory across the ecosystem. As publishers adopt ads.txt, buyers will be able to more easily identify the Authorized Digital Sellers for a participating publisher, allowing brands to have confidence they are buying authentic publisher inventory.

What is ads.txt?

Ads.txt is a simple, flexible, and secure method for publishers and distributors to declare who is authorized to sell their inventory, improving transparency for programmatic buyers.

Ads.txt supports transparent programmatic digital media transactions and can remove the financial incentive from selling counterfeit and misrepresented media. Similar to robots.txt, ads.txt can only be posted to a domain by a publisher’s webmaster, making it valid and authentic. As a text file, ads.txt is easy to update, making it flexible. The data required to populate the file is readily available in the OpenRTB protocol, making it simple to gather and target. And because publishers sell their inventory through a variety of sales channels, ads.txt supports the following types of supplier relationships:

Domain owners who sell on exchanges through their own accounts

Networks and sales houses who programmatically sell on behalf of domain owners

Content syndication partnerships where multiple authorized sellers represent the same inventory

What Problem Does Ads.Txt Solve?

The ads.txt project aims to prevent various types of counterfeit inventory across the ecosystem by improving transparency in the digital programmatic supply chain.

When a brand advertiser buys media programmatically, they rely on the fact that the URLs they purchase were legitimately sold by those publishers. The problem is, there is currently no way for a buyer to confirm who is responsible for selling those impressions across exchanges, and there are many different scenarios when the URL passed may not be an accurate representation of what the impression actually is or who is selling it. While every impression already includes publisher information from the OpenRTB protocol, including the page URL and Publisher.ID, there is no record or information confirming who owns each Publisher.ID, nor any way to confirm the validity of the information sent in the RTB bid request, leaving the door open to counterfeit inventory.

Counterfeit inventory – is defined here as a unit of inventory sourced from a domain, app or video that is intentionally mislabeled and offered for sale a different domain, app or video. The motivation to create counterfeit inventory comes in many forms including, to sell invalid traffic (automated non-human, or incentivised/mislead human traffic) by hiding it in real traffic, to attract higher prices by mislabeling inventory as brand inventory, to bypass content or domain blacklists, or to capture advertising spend restricted to whitelisted domains, among others.

Note that this form of “inventory fraud” in advertising is independent of how the traffic is generated. It can potentially include a mix of for example automated (non-human) bot traffic and real human user traffic. It can also exist as a small amount of authentic and valid inventory mixed with mislabeled inventory.

How Does Ads.Txt Work?

Ads.txt works by creating a publicly accessible record of authorized digital sellers for publisher inventory that programmatic buyers can index and reference if they wish to purchase inventory from authorized sellers. First, participating publishers must post their list of authorized sellers to their domain. Programmatic buyers can then crawl the web for publisher ads.txt files to create a list of authorized sellers for each participating publisher. Then programmatic buyers can create a filter to match their ads.txt list against the data provided in the OpenRTB bid request.

Example: Example.com publishes ads.txt on their web server listing three exchanges as authorized to sell their inventory, including Example.com’s seller account IDs within each of those exchanges.

http://example.com/ads.txt:

#< SSP/Exchange Domain >, < SellerAccountID >, < PaymentsType >, < TAGID >

greenadexchange.com, 12345, DIRECT, AEC242

blueadexchange.com, 4536, DIRECT

silverssp.com, 9675, RESELLER

Note: The seller’s Publisher.ID will be specified in the “SellerAccountID” field in the ads.txt.

A buyer receiving a bid request claiming to be example.com can verify if the exchange and SellerAccountID matches the authorized sellers listed in example.com/ads.txt file.

What Is The Ads.Txt Project?

The mission of the ads.txt project is simple: Increase transparency in the programmatic advertising ecosystem. ads.txt stands for Authorized Digital Sellers and is a simple, flexible and secure method that publishers and distributors can use to publicly declare the companies they authorize to sell their digital inventory.

By creating a public record of Authorized Digital Sellers, ads.txt will create greater transparency in the inventory supply chain, and give publishers control over their inventory in the market, making it harder for bad actors to profit from selling counterfeit inventory across the ecosystem. As publishers adopt ads.txt, buyers will be able to more easily identify the Authorized Digital Sellers for a participating publisher, allowing brands to have confidence they are buying authentic publisher inventory.

IAB Tech Lab Adds Ads.Txt Values To Help Buyers Determine The Owner And Manager Of Inventory

New York, NY (April 13, 2022) – Today, IAB Tech Lab, the digital advertising technical standards-setting body, announced an update to the widely adopted ads.txt specification which they have opened for public comment for 60 days.

The update includes two new values for publishers to declare within their ads.txt files, “ownerdomain” and “managerdomain” which helps  increase the transparency into seller relationships via sellers.json and further strengthens ads.txt as a tool to reduce fraud in buying and selling of advertisements on websites, mobile apps and connected TV.

The “ownerdomain” value is used to specify the domain of the business that owns the website that the ad is being served on. This helps to connect the seller domain for PUBLISHER entries in sellers.json files, which has previously been hard to programmatically validate resulting in mismatched seller domains, especially when an entity owns multiple publisher properties.

“Owner domain provides a critical link between the business entity being paid, and listed in a sellers.json file and the ads.txt file on the site being monetized. Publicly connecting these dots closes a potential gap that allows for misrepresentation,” said Neal Richter, Chairman of the Board of Directors, IAB Tech Lab.

The “managerdomain” enables the publisher to declare the primary or exclusive monetization partner of that sites inventory. This new addition to ads.txt will help to level the supply path optimization (SPO) playing field for small to medium publishers. This is because publishers that outsource yield management, and transact under their manager’s seller ids are automatically made to appear as though they have multiple hops to access their inventory; this is a challenge when supply path optimization’s focus on buying from the fewest number of hops in the supply chain to access inventory. The addition of the Manager Domain in ads.txt will helps buyers know that even with multiple hops, this may be the most optimal route to access that publisher’s inventory.

Paul Bannister, Chief Strategy Officer of CafeMedia said, “We are excited to use the manager domain field with our publishers to give buyers more clarity that buying a given publisher through us is the most optimal path to buy that inventory. While our entries have always been in the publisher’s ads.txt file, the manager domain value provides an unambiguous link between our sellers.json entry in exchange’s sellers.json files and the publisher’s ads.txt file, providing buyers with a clear understanding of supply path.”

“Overall these two new values help to bring more transparency to the supply chain by enabling advertisers to better identify and control who their spend is going to,'” Said Shailley Singh, Vice President of Product, IAB Tech Lab. “This helps to further combat fraud, minimize the loss of revenue for advertisers, and helps to ensure spend is being directed to the right places, all of which is essential for the sustainability of our industry.”

The public comment period for ads.txt 1.1 will run through May 31, 2022, after which the IAB Programmatic Supply Chain Working Group Ads.txt Subgroup, which developed the tool, will evaluate the comments received. It will then make any necessary revisions, and release a final version. 

About IAB Technology Laboratory

Established in 2014, the IAB Technology Laboratory (Tech Lab) is a non-profit consortium that engages a member community globally to develop foundational technology and standards that enable growth and trust in the digital media ecosystem. Comprised of digital publishers, ad technology firms, agencies, marketers, and other member companies, IAB Tech Lab focuses on solutions for brand safety and ad fraud; identity, data, and consumer privacy; ad experiences and measurement; and programmatic effectiveness. Its work includes the OpenRTB real-time bidding protocol, ads.txt anti-fraud specification, Open Measurement SDK for viewability and verification, VAST video specification, and Project Rearc initiative for privacy-centric addressability. 

File format

The IAB's ads.txt specification dictates the formatting of ads.txt files, which can contain three types of record; data records, variables and comments. An ads.txt file can include any number of records, each placed on their own line.

Since the ads.txt file format must be adhered to, a range of validation, management and collaboration tools have become available to help ensure ads.txt files are created correctly.

Latest specification v1.0.2 recommends using a placeholder record to indicate the intent of an empty ads.txt file: placeholder.example.com, placeholder, DIRECT, placeholder

State of adoption

By November 2017, more than 44% of publishers had ads.txt files. More than 90,000 sites were using ads.txt, up from 3,500 in September 2017, according to Pixalate. Among the top 1,000 sites that sold programmatic ads, 57 percent had ads.txt files, compared to 16 percent in September, per Pixalate.

Latest adoption data per FirstImpression.io's Ads.txt Industry Dashboard:

Websites Tier	Jan 30th, 2020	Jan 30th, 2019	Jan 30th, 2018
Alexa Top 1,000	44.20%	40.90%	33.70%
Alexa Top 5,000	39.58%	36.00%	29.06%
Alexa Top 10,000	36.66%	32.75%	25.18%
Alexa Top 30,000	31.71%	26.34%	18.52%

Google has been an active proponent of ads.txt and pushing for faster, widespread adoption by publishers. From the end of October 2017 Google Display & Video 360 only buys inventory from sources identified as authorized sellers in a publisher’s ads.txt file, when a file is available. ads.txt may become a requirement for Display & Video 360.