Understanding Ads.txt and Sellers.JSON Files

Key Takeaways

• Ads.txt and Sellers.json are crucial tools for increasing transparency and reducing fraud in digital advertising by verifying the legitimacy of sellers and preventing unauthorized reselling.
• Ads.txt allows publishers to list authorized sellers of their ad inventory, significantly reducing domain spoofing and building advertiser trust.
• Sellers.json provides additional transparency by revealing the relationships between entities in the ad supply chain, helping buyers verify sellers and trace the origin of ad inventory.

Sadly, the internet is no stranger to fraud. There are bad actors found throughout the web, so it’s important for all legitimate parties to have ways to find each other and keep the troublemakers out of the way. That’s easier said than done, of course, which is why tools like ads.txt and sellers.json have been developed to help root out the scammers.

If you don’t know what those initiatives are or why they play an important role in digital advertising, don’t worry – we will get to that below. By the end of this page, you’ll understand these two tools and how they can keep you safe while engaging in digital advertising on either the promotional or publishing side of the coin.

Solving a Complex Problem

The issue at hand here is the fact that some fraudsters online attempt to represent themselves as part of a brand, company, or organization that they do not actually represent. For example, a shady company may act like they have the right to sell digital ads for a certain clothing brand when they do not actually have that right. It can be difficult for other parties online to sort out what is real and what is fake with this kind of scheme.

So, both ads.txt and sellers.json have been developed as a way to get around this issue. While no online security solutions are perfect, these are effective tools and go a long way toward eliminating this kind of fraud.  

What is Ads.txt?

The goal of ads.txt is to allow publishers to create a list of companies that are authorized to sell their digital ad inventory. It was created by the Interactive Advertising Bureau and has been effective in preventing ad fraud.

It is pretty simple in the way it functions, as all a publisher has to do is add an ads.txt to their root domain. Because they should be the only party that has access to place things on the root domain, other parties can believe the legitimacy of the file when they go to this URL. In that file, there should be a list of companies and some basic information about them. This is a quick and easy way to verify if a given ad exchange or reseller actually has the permission needed to legally sell ad inventory.

The Value of Ads.txt

1. Reduction in Ad Fraud – Ads.txt helps combat domain spoofing, a type of ad fraud where a bad actor pretends to be a legitimate publisher to sell ad space. Studies have shown that the implementation of Ads.txt significantly reduces instances of this kind of fraud. For example, research conducted by Google and other ad tech companies has indicated a notable decrease in the prevalence of fraudulent inventory after widespread adoption of Ads.txt.
2. Clearer Supply Chains – By listing authorized sellers, Ads.txt makes the digital ad supply chain more transparent. This allows advertisers to verify that they are buying legitimate ad space from trusted sources, thereby reducing the chances of purchasing counterfeit inventory. Research has highlighted that advertisers are more willing to invest in inventory that is verified through Ads.txt, which can enhance the revenue potential for publishers who use it.
3. Widespread Use – A study by the IAB Tech Lab found that within a year of its introduction, Ads.txt was adopted by over 70% of the top 1,000 U.S. websites selling programmatic ads. The broad adoption has led to an industry-wide improvement in trust and a reduction in the need for complex and costly third-party verification systems.
4. Effect on CPMs (Cost Per Thousand Impressions) – There is evidence that the use of Ads.txt can lead to higher CPMs. Advertisers are generally willing to pay a premium for inventory that is certified as legitimate, given the reduced risk of fraud.

The Challenges and Limitations of Ads.txt

1. Incomplete Adoption – Despite its benefits, some research points out that not all publishers have adopted Ads.txt, leading to an incomplete solution to ad fraud. Moreover, the effectiveness of Ads.txt can be limited if the files are not maintained or updated properly, as outdated entries might inadvertently authorize unwanted sellers.
2. Evasion Tactics – Fraudsters have attempted to circumvent Ads.txt by engaging in tactics such as subdomain hijacking or setting up fake Ads.txt files. While the industry continues to evolve to counter these tactics, it is an ongoing challenge.

Ads.txt file has proven to be a valuable tool in enhancing transparency, reducing fraud, and improving the trustworthiness of the digital advertising ecosystem. While it is not a complete solution and does have some limitations, its widespread adoption has had a positive impact on the industry. Ongoing efforts to improve and expand upon Ads.txt (such as with Ads.cert) indicate a continued commitment to addressing the challenges of ad fraud.

What is Sellers.json?

In many ways, sellers.json is quite similar to ads.txt. Only, in this case, the point is to offer transparency into the intermediaries involved in the ad market. These intermediaries can include parties such as supply-side platforms, ad exchanges, and demand-side platforms. The JSON file is hosted by the intermediaries and provides critical information about companies who are selling and buying ad space through the platform.

Again here, the file is hosted on the domain of the intermediary. It will list the sellers they work with so anyone can visit that file and quickly scan it to confirm whether or not a seller is legitimate and has the permission needed to buy or sell on the platform.

You can think of sellers.json as a way to cut through the noise and confusion of the ad supply chain. Using this one file, it will be much easier to trace how the ads are moving and what parties are involved in these transactions.

Value of Sellers.json Files

1. Identifying Sellers – Sellers.json files contain information about the entities (sellers or resellers) involved in the sale of digital advertising inventory. By making this information public, it helps advertisers and other buyers to know who they are buying from, increasing transparency in the ad ecosystem.
2. Trust and Accountability – With Sellers.json, buyers can verify the legitimacy of sellers, ensuring they are purchasing from trusted sources. This helps in reducing fraudulent activities and encourages accountability among sellers and intermediaries in the supply chain.
3. Preventing Unauthorized Sales – Similar to Ads.txt, Sellers.json helps prevent unauthorized sales of ad inventory. It enables buyers to trace the supply chain back to the original source, making it harder for fraudsters to insert fake or misrepresented inventory into the market.
4. Combating Ad Fraud – While Ads.txt provides a list of authorized sellers for a particular domain, Sellers.json gives additional context by revealing the relationships between entities, making it easier to detect suspicious activity or non-transparent practices.
5. Streamlining Ad Supply Chains – Sellers.json data can be used by advertisers and agencies to optimize their supply paths by choosing more direct and transparent routes to purchase inventory. This can lead to cost savings and more efficient media buying.
6. Reputation Building for Sellers – Sellers who are transparent about their business practices by including detailed and accurate information in their Sellers.json file can build a positive reputation in the industry. Buyers may prefer to work with these sellers, leading to more business opportunities.

Challenges of Sellers.json Files

1. Data Accuracy and Maintenance – For Sellers.json to be effective, it needs to be regularly updated and maintained. Inaccurate or outdated information can lead to misunderstandings or misidentification of legitimate sellers, potentially harming business relationships.
2. Technical Expertise Required – Implementing and maintaining Sellers.json files requires a certain level of technical expertise, particularly for smaller publishers or intermediaries who may not have the resources to manage this effectively.
3. Public Disclosure of Relationships – Sellers.json files make the relationships between sellers and resellers public, which could raise privacy concerns. Some entities may be reluctant to disclose their business relationships due to competitive reasons or concerns over the misuse of this information.
4. Varied Levels of Adoption – Not all publishers or intermediaries have adopted Sellers.json, which can lead to gaps in the data. This incomplete adoption limits the effectiveness of Sellers.json in providing full transparency across the entire digital ad ecosystem.
5. Does Not Provide Full Transparency – While Sellers.json adds an important layer of transparency, it does not cover all aspects of the ad supply chain. For instance, it does not reveal the full financial details of each transaction, such as the exact fees or margins taken by intermediaries.
6. Inconsistencies in Data Formats – Although there is a general structure for Sellers.json, there can be inconsistencies in how different entities implement and populate their files. This lack of standardization can make it difficult for buyers to accurately interpret the data.
7. No Direct Penalties – There is no enforcement mechanism built into the Sellers.json standard, meaning that entities that choose not to implement or maintain accurate files do not face direct penalties. This can limit the incentive for full compliance.

These Tools Deliver Powerful Benefits

Fraud prevention is at the heart of what ads.txt and sellers.json are all about. Unauthorized reselling is a problem in the ad space but it can quickly be uncovered by using these freely available resources. Transparency goes way up when either of these protocols is followed, and when transparency goes up, fraud tends to go down in the opposite direction.

Not only do these files help to root out fraud, but they do so in an efficient and simplified manner. Rather than having to manually verify the legitimacy of a seller, for instance, these tools can be used to grab the needed information quickly and be sure that the money being spent on ads is going to the right place. Advertisers who are putting valuable dollars from their budget into purchasing space with publishers need to know that those dollars are being spent in a safe and effective manner – and without ads.txt and sellers.json, it would be much harder to have the confidence needed to spend freely.

No tactics are completely foolproof when it comes to fraud prevention online, but the strategy behind these two tactics is strong and they can be considered excellent resources to be used to build trust in the online advertising landscape as a whole. Whether you have previously fallen for a domain spoofing scam or you just want to cover your bases and make it less likely that you’ll ever be scammed out of important ad spend, understanding ads.txt and sellers.json is a big step in the right direction.