Categories: Tips

ads.txt – What is ads.txt? How to implement for AdSense and others

If you haven’t heard of it yet, be prepared to hear a lot about ads.txt in the coming months. The clumsily named ads.txt project (pronounced “ads dot tee ex tee”) is the digital advertising industries initiative to clean up digital advertising and bring transparency to advertising. Although this has almost immediate impact on publishers, including those just using AdSense, many publishers are still unaware of it.  The initiative came about in the wake of a number of scandals around the misrepresentation of ad inventory that resulted in big money being spent on bad inventory. The solution, backed by the IAB and most of the big players in the ad space is deceptively simple (and for once cheap and easy for publishers of all sizes to implement).

Update October 2017: Google have announced that from October 15th they will stop buying inventory from sites that have an ads.txt file that doesn’t match the ad request. This means that it is imperative that publishers have their ads.txt correctly set-up right away if they have the file present.  Google are not yet blocking buys from sites with no ads.txt files, but this will follow.  For now the biggest risk is from incorrectly implemented ads.txt files. For examples of implementing ads.txt for AdSense and Ad Exchange either scroll down or click here.

How does ads.txt work?

Ads.txt is simply a text file that sits on your server and lists the places authorised to sell ads on your behalf. The “ads” part of the name is an acronym for “Authorised Digital Sellers”. The idea is simple: Buyers can collect this data and be sure that if they’re paying for ads on rollingstone.com then that is where those ads will appear (see example from rollingstone.com/ads.txt) .

The file simply lists the accounts that are authorised to sell the inventory, doing so in a format that can be easily crawled and indexed.

What do publishers stand to gain from implementing ads.txt?

If you are the New York Times, the benefit is obvious: Advertisers looking for exposure on your site won’t be tricked into buying misrepresented inventory and you retain control over pricing. As the standard gains more widespread adoption buyers are more likely to require ads.txt for all buys, making it more relevant to less well known publishers too.

Q: What are the drawbacks of implementing ads.txt?

The initiative is not without some criticism. Ads.txt is designed to bring transparency, but some argue that it is too transparent. Implementing ads.txt shows exactly where you sell your inventory to anyone who cares to look. If you price your ad inventory differently through different channels this allows buyers to shop around for the lowest price

Take, as an example, the ads.txt file for Business Insider :

#Ads.txt uk.businessinsider.com

google.com, pub-1037373295371110, DIRECT #video, banner, native, app
rubiconproject.com, 10306, DIRECT #banner
indexexchange.com, 183963, DIRECT #banner
indexexchange.com, 184913, DIRECT #banner
openx.com, 537147789, DIRECT #banner
openx.com, 538986829, DIRECT #banner
appnexus.com, 7161, DIRECT #banner
appnexus.com, 3364, RESELLER #native
facebook.com, 1325898517502065, DIRECT #video, banner, app
liveintent.com, 87, DIRECT #banner
taboola.com, 688168, DIRECT #native
triplelift.com, 4139, DIRECT #native
teads.com, 11643, DIRECT #outstream
teads.com, 11445, DIRECT #outstream
google.com, pub-8415620659137418, RESELLER #native

If I’m buying ads on Business Insider through one of these partners I can easily see where else inventory is available. I even have the relevant account IDs should I care to go comparing prices. Business Insider have even gone one step further and kindly labelled each demand partner with the types of ads they serve, although this is not part of the standard.

Again, these are “big publisher problems” that many independents would like to face, but are important to be aware of.

Should publishers adopt ads.txt?

Compared with other initiatives publishers are encouraged to adopt, the implementation cost of ads.txt is incredibly low. Five minutes work is enough to get most sites compliant, but despite this adoption hasn’t yet been overwhelming.  According to BuiltWith, only 1.8% of the top 10,000 websites currently use ads.txt, compared with over 44% using DoubleClick (not an entirely fair comparison, as both buy and sell side have reason to implement DoubleClick code, but a useful benchmark). Unsurprisingly, adoption is being led by USA, Germany and the UK.

Currently ads.txt is in a bit of a chicken and egg situation. There is not real drive for publishers to implement it until buyers start filtering to only buy from ads.txt supporting sources. Buyers aren’t implementing those filters yet, as there isn’t enough inventory until more publishers implement. Whether or not the initiative will gain enough momentum to get widespread adoption remains to be seen and is likely to be led by major publishers.

There could potentially be an early adopter advantage to those who have ads.txt in place if/when buyers start filtering on its use. The low cost and ease of adoption means that this could suit independent publishers who aren’t concerned about the transparency issue and have the flexibility to rule out change more easily.

Implementing ads.txt for Google ads (AdSense and Ad Exchange)

Implementing ads.txt is incredibly simple. Create a text file and add one line per authorised partner. On each line add the following three pieces of information, separated by a comma:

  • The domain of the advertising system
  • Your account ID
  • The type of relationship you have with that partner (either DIRECT or RESELLER if you are working through a third party)

There is an optional 4th field which is the TAG ID of the source if they are certified by the Trustworthy Accountability Group.  Once created simply upload that file to your webserver so that it is visible at example.com/ads.txt and you are done.

Google are pushing hard on ads.txt . Whilst they haven’t said that they will stop bidding on inventory that doesn’t have a corresponding ads.txt file, they will stop buying and selling unauthorised inventory in Q4 2017. In practice that means that there is more immediate risk to AdSense and Ad Exchange publishers from badly implementing ads.txt than not implementing it. This makes it doubly important to ensure that:

  1. If you use an ads.txt file you must include declarations for an AdSense and Ad Exchange accounts that you serve
  2. Those declarations need to be correct

ads.txt for AdSense

If you publish ads via Google AdSense and want to implement ads.txt you will need to first locate your publisher ID.  This can be found by logging in to AdSense and then navigating to Settings > Account > Account information.  Your publisher ID is in the format of pub-0000000000000000 with the zeros replaced by your own 16 digit number.

The entry in ads.txt for a publisher’s own Google AdSense account will then look like:

google.com, pub-0000000000000000, DIRECT, f08c47fec0942fa0

Please note that the TAGID for Google is always f08c47fec0942fa0 . Also, don’t forget to include the pub- part of your publisher ID, as this is apparently one of the most common errors in ads.txt implementation for AdSense publishers.

Update October 16th: AdSense publishers are now starting to see warnings in their account regarding ads.txt . The warning states Earnings at risk – One or more of your ads.txt files doesn’t contain your AdSense publisher ID. Fix this issue now to avoid severe impact to your revenue.

This in-account warning complements notices that are being sent by email in the following format:

Dear Publisher,
We’ve noticed that the ads.txt file on one or more of your sites that you monetise through this AdSense account (pub-xxxxxxxxxxxxxxxx) is missing the correct publisher code.
From mid-October, Google will stop buying ads on sites with ads.txt files which don’t include the correct publisher IDs. We recommend you update your ads.txt files immediately to prevent impact to your earnings. Make sure that the ads.txt file for each site you want to monetise through this account contains the snippet below:
google.com, pub-xxxxxxxxxxxxxxxx, DIRECT, f08c47fec0942fa0
It may take up to 24 hours for AdSense to process your updated ads.txt files.
You can learn more about ads.txt, how buyers will use it and how to implement it on your sites in our Help Centre.


ads.txt for Ad Exchange

The set-up for publishers with their own direct DoubleClick Ad Exchange account is the same, with the ID being found through DFP by navigating to Admin > Global settings > All network settings. Again the Publisher ID is in the format of pub-0000000000000000.

For publishers accessing Ad Exchange through a GCPP (such as OKO) or other third party the process is the same, but they will need to get the publisher ID from their managing partner and specify it as reseller. To take the example of a publisher using their own AdSense account and accessing Ad Exchange through a partner, their ads.txt file will look like the example below (We’ve labelled with a #comment for clarity):

google.com, pub-0000000000000001, DIRECT, f08c47fec0942fa0 # own adsense
google.com, pub-0000000000000002, RESELLER, f08c47fec0942fa0 # AdX

Mat Bennett :

View Comments (30)

  • Hi - last Friday (12th) ads stopped displaying on my site and I started receiving the warning about missing ads.txt in the AdSense portal. I added it to my site, copying and pasting the recommended content from the Google notification. However since then I still have no adverts (and no revenue), and still have the warning. The ads.txt is clearly browsable. I have no AdSense crawler errors and no policy issues.

    Any ideas?

  • Hi
    Should I use ads.txt file, because on some of my pages Google ads are not displaying.
    By the way is it necessary for every adsense publisher to use ads.txt file?

  • I received the message today on my account, i have not realized how to go about the solution to the issue, when I Googled it in order to know what is all about, then I stumbled on your website! As I'm typing now, Google ads have stopped showing on my website. Pls, what can I do to stop the problem? Do I need to edit my site html? Where should I add the ads.txt code? Please I need your answer. Thanks

  • The below procedure will work for those using blogger blog:

    STEP 1: Go to Blogger dashboard

    STEP 2: On left-handed menu; choose "Settings"

    STEP 3: Click "Search preferences"

    STEP 4: You will see new option at the bottom side of right pane "Monetization"

    STEP 5: You will see "Custom ads.txt" option to edit.

    STEP 6: Add the settings provided by all your 3rd party Ad networks and "Save" settings.

    STEP 7: You then able to check the Ads.txt file by going to the URL like "https:www.yourwebsiteurl.com/ads.txt"

    I found it after my search through the Internet in order to my adsense showing on my website again.

    • We don't tend to work on Blogger sites, so I haven't checked this - but that sounds like a great solution Solomon. Thanks for sharing it here.

  • hallo i have the same error message. and I use domain with blogspot as its hosting. if anyone can overcome this error please info me

  • Thanks for this update dear.
    I have just added mine through the setting>>monetization feature on blogger but i am yet to see the ads.

    Before implementing on my blog, ads spaces were blank. More like ads display was stopped till i implement this or what?