Why ads.txt is important for your website

Have you heard about ads.txt, but perhaps the details still seem elusive? Or perhaps you’re familiar with the concept, but the importance of its implementation remains a little unclear? No worries, we are here to demystify it all.

But what exactly is ads.txt? How does it work and more importantly, why is it so essential for the security and efficiency of your website?

We explain everything to you 👇

What is ads.txt?

Ads.txt, or “Authorized Digital Sellers”, is a simple text file that publishers use to publicly declare the companies authorized to sell their advertising inventory. The Interactive Advertising Bureau (IAB) introduced ads.txt in 2017 to increase transparency and combat fraud in the online advertising ecosystem, allowing buyers to verify the sellers authorized by publishers.

Ads.txt is an essential tool to clarify the programmatic advertising landscape, which can often seem complex and opaque. To learn more about programmatic advertising, check out our dedicated article: The programmatic digital advertising market.

Let’s take the example of Le Monde using ads.txt to manage its ad sellers. By accessing lemonde.fr/ads.txt, buyers can view the list of authorized sellers, such as Google or AppNexus, with detailed information like their unique ID and their type of relationship (direct or reseller).

This verification prevents the unauthorized sale of ad space, thus avoiding fraud and quality issues.

How does ads.txt work?

The ads.txt file is a mechanism by which publishers publicly declare the entities authorized to sell their advertising inventory. Here’s an overview of how it works:

✅ Publication on the publisher’s site: the publisher places a text file named “ads.txt” at the root of their domain. This file is publicly accessible via the URL (e.g., www.example.com/ads.txt).
✅ File content: the file lists the domain names of authorized sellers, their unique IDs, the type of relationship (direct or reseller), and sometimes a certification ID from the authority.
✅ Utility for buyers: ad buyers use this file to verify that the sellers they deal with are legitimately authorized to sell ad space on the publisher’s site. This helps avoid fraudulent transactions and ensures transparency.

Example of an entry in an ads.txt file:

example.com, 12345, DIRECT, abcdef12345

✅ “example.com” is the seller’s domain name;
✅ “12345” is the seller’s account ID;
✅ “DIRECT” indicates that the seller is a direct partner of the publisher;
✅ “abcdef12345” is the seller’s certification, which can be obtained from the IAB Tech Lab.

In general, ads.txt communicates to ad buyers: “Here are the reliable ad sellers on this site. If you’re interested in buying ads, prioritize these options!”

How to create your ads.txt file?

Creating an ads.txt file is a simple and straightforward process. Here are the steps to establish and maintain this component of your ad monetization strategy:

• Open a text file: use a basic text editor like Notepad on Windows or TextEdit on Mac to start composing your file.
• List authorized sellers: write down the domain names of ad sellers authorized to sell your ad inventory. Here are some examples of typically authorized seller domains:

google.com
appnexus.com
rubiconproject.com

These are examples of authorized ad seller domains.

• Add identifiers: for each seller, include additional details that facilitate identification and validation. For example:

google.com, 12345, DIRECT, f08c47fec0942fa0
appnexus.com, 56789, RESELLER, 5jy2hj8768kj

While IDs and certifications are not mandatory, they are recommended to improve tracking and security.

• Save your file: once your list is complete, save the file as “ads.txt” and make sure to place it at the root of your website. This is where ad buyers will expect to find it, for example at www.yourcompany.com/ads.txt.
• Publish the file on your site: finally, upload the file to your site. This will allow ad buyers to easily verify with whom they can contract securely.

Keep in mind that ads.txt is a transparency tool that helps protect your ad revenue by ensuring that only authorized sellers can market your ad space. Therefore, it is necessary to keep it up to date by adding new sellers or removing those who are no longer authorized.

What does IAB Tech Lab do?

Now, you might be wondering who is behind all this. Well, IAB Tech Lab is a branch of the Interactive Advertising Bureau (IAB). This group is dedicated to innovation and adopting best practices to maximize the benefits of online advertising for all industry players.

The IAB Tech Lab focuses on developing standards and technical solutions for the digital advertising industry. The IAB ad standard includes specifications for ads.txt, which provides a list of authorized ad sellers by the publisher. This allows ad buyers, such as DSPs – Demand Side Platforms – to verify the authenticity of the ad inventory they purchase and ensure it comes from legitimate sources.

In summary, the IAB Tech Lab ensures that market players have the necessary tools to operate transparently and securely in the online advertising ecosystem.

What is the IAB ad standard?

The IAB ad standard, developed by the IAB Tech Lab, unifies online advertising practices with tools like ads.txt, sellers.json and app-ads.txt, improving collaboration between publishers and buyers. For publishers and advertisers, understanding the IAB ad standard is crucial to facilitate industry interactions, avoid misunderstandings, and save time and money.

The IAB ad standard also includes specifications for ad formats, ensuring that ads not only meet modern design and functionality expectations but are also optimized for various devices and platforms. These formats, detailed in the IAB New Ad Portfolio Guidelines, encourage the use of flexible, responsive, and user-centered ad formats that adapt to various screens without compromising user experience.

Why update your ads.txt?

For a long time, the cleanliness of the ads.txt file has been neglected by the entire online advertising market. Today the trend is changing: more and more publishers and DSPs are streamlining the often overloaded ads.txt file. Major publishers like Les Echos and Le Parisien have started removing unnecessary lines. For more details on French publishers and their advertising partners, check out the site of Mind media.

Regularly updating your ads.txt file has several advantages:

• Transparency and fraud prevention: by listing authorized sellers in your ads.txt, you reduce the risk of fraud and unauthorized traffic on your site.
• Increased buyer confidence: an up-to-date ads.txt increases buyer confidence, affirming the legitimacy of your ad inventory.
• Optimization of ad revenue: a well-managed ads.txt improves collaboration with programmatic partners, thus increasing monetization opportunities for your sites.

📝 For example:

You are the owner of a well-established news site. You work with several DSPs to display ads on your site. However, you have recently noticed a decline in your ad revenue, and you do not understand why. By checking your ads.txt file, you realize that some lines are obsolete because you no longer work with certain partners. By updating your ads.txt and removing outdated entries, you help buyers identify authorized sellers, thus optimizing your ad revenue.

This concrete example shows how ads.txt can play an important role in protecting your site and your audience from ad fraud, while improving the relevance of displayed ads.

Major publishers recognize the importance of ads.txt. By adopting this standard, they demonstrate their commitment to combating ad fraud and promoting a better online advertising experience.

How to update your ads.txt?

Updating your ads.txt is not complicated at all, here are some steps to know:

• Identify your advertising partners: start by reviewing your current advertising partners. These are the ones who help you monetize your site by displaying ads. Note their domain names.
• Verify the information: make sure you have the correct information about each of these partners. You need their domain name (like friendlyads.com) and their seller ID (it looks like “pub-1234567890”).
• Open your ads.txt file: you can open your site’s ads.txt file with a simple text editor.
• Add new lines: for each partner, add a new line to your ads.txt file. It looks like this:

partner-domain.com, partner-id, DIRECT, reseller

• Remove outdated entries: if some of your advertising partners are no longer active or if you have stopped working with them, it is important to remove their information from your ads.txt file. This ensures that the file remains up-to-date and free from any unnecessary references, improving its accuracy and reliability.

📝 Concrete examples:

Case No. 1: suppose you have a new partner, “NewAds”. Their domain is “newads.com” and their ID is “pub-new1234”. Just add this line to your ads.txt file:

newads.com, pub-new1234, DIRECT, reseller

Case No. 2: if you are no longer partnered with “OldAds” it is essential to immediately remove their information from your ads.txt file. This avoids any confusion or unauthorized transactions, ensuring that only current partners are listed.

Using the Adrenalead Notifadz plugin

Notifadz simplifies this technical update. Our plugin handles the integration and automatic management of the ads.txt file, ensuring compliance with web standards without additional effort on your part.

In conclusion, adopting and maintaining ads.txt is essential to ensure transparency, prevent fraud, and maximize ad revenue. This simple file allows publishers and ad buyers to collaborate with confidence, ensuring that only authorized sellers can access your ad inventory. By following the standards established by the IAB Tech Lab, you are investing in the security and efficiency of your ad space.