What we learned about programmatic from studying the ads.txt files of Australia’s top domains

Automatad's Vamsi Krishna and Rasheed Ahamed had been wondering about the state of programatic selling in Australia - so they decided to take things into their own hands.

Zenith’s latest programmatic marketing forecast predicts over two-thirds of Australian digital display ad spend will be bought through programmatic platforms by 2020. The report also expects that the total programmatic ad spend will rise to $2.92bn by next year.

But the prediction is far from answering any specific questions. What percentage of publishers are actually using programmatic channels to sell their impressions? Who is the preferred monetization partner?

So, we decided to take a look at the state of programmatic selling in Australia by studying the ads.txt files of the top 2000 domains in the country.


We compiled the top 2000 Alexa domains in Australia and removed the sites that belong to walled gardens like Google, Facebook, Snap, etc. We also excluded the non-brand safe content sites, .gov and .edu domains, and brand sites before running the analysis. After all that, we were left with 1,626 publishers to crawl. We built the ads.txt crawler in-house and used it to run the analysis.

Percentage of publishers using programmatic

Of 1,626 publishers, 626 have an ads.txt file hosted on their servers.

Media buyers have the ability to exclude publishers without ads.txt files. Google’s Display & Video 360, one of the biggest demand-side platforms in the market, enabled the opt-in last July to curb unauthorized sellers. This means publishers who aren’t hosting a simple text file are missing out the lucrative bids from buyers.

Approximately, 1.1% of the 626 publishers run only AdSense, which is an ad network (non-programmatic). So, 38.61% of publishers are selling their ad impressions programmatically to the buyers.

Popular ad monetization partners

Direct partners

Google, as expected, is the most popular “direct” partner. Across the 2000 sites, Google has been listed over 2,470 times as a direct partner in publishers’ ads.txt files. Roughly 98% of the publishers use Google to monetize their traffic.

It shows Google, no matter the market, has already captured the majority of the publishers. The reason is quite simple – Google’s ad exchange (Google AdX) has the biggest demand pool for the publishers and the company also runs an ad network, not just an ad exchange. Publishers end up using Google, one way or another.

Interestingly, Taboola, a native advertising provider, amassed over 1700+ mentions. We believe the minimum traffic requirement is one of the important reasons for the popularity. Unlike ad exchanges, Taboola accepts publishers with a relatively lesser number of page views per month.

Here are the top five direct partners.


Surprisingly, AppNexus is the most-used reseller, as per the ads.txt files of top publishers. Google and OpenX completed the top three.

Publishers reach the exchanges they can’t get by themselves with the help of resellers. In other words, ad exchanges are getting access to the aggregated supply through the resellers.

For instance, AppNexus has increased its publisher base 21 percent with the help of resellers. Similarly, Freewheel.tv added 144 percent more publishers with reseller accounts.

Side note: Google didn’t increase its reach with the help of resellers. Apparently Google was able to partner with almost all the publishers directly.

Direct partners vs resellers

More than 65% of the ads.txt lines are for resellers, and 33% of the lines are for direct partners. Note that the total wouldn’t equal to 100%, as there are some formatting errors in the files.

Comparing the other markets, Aussie’s top publishers tend to have a direct relationship with the ad exchanges. In fact, 99.5% of the publishers have listed at least any one of the ad exchanges as a direct partner in their ads.txt files.

And, a little over 10% of the publishers have only direct accounts, with no reseller accounts at all.

Average accounts and partners

On average, publishers in the top 2k cohort have 160 accounts with 35 ad tech partners. However, a handful of ad tech partners own the majority of the supply.

What’s next?

Programmatic media buyers are increasingly shifting towards ads.txt publishers to prevent fraudsters from siphoning their budgets. Publishers have already proven the effectiveness of ads.txt and how it stopped domain spoofing.

When there’s no ads.txt, buyers essentially are throwing their money into an open vault. It’s only a matter of time before fraudsters to sneak in and steal the budget. Both resellers and exchanges should start mandating the presence of ads.txt files.

In addition, publishers should apportion their supply to different ad exchanges, not just Google. The more the exchanges, the higher the competition, and the better the bid prices. Only then will publishers will get to know the real market value of their impressions.

Vamsi Krishna is technical lead and Rasheed Ahamed is an inbound marketer at Automatad.


The study relies on the ads.txt files of publishers and uses the same to depict the percentage of publishers selling the inventories programmatically. However, the actual percentage would be higher as the ads.txt adoption rate isn’t likely to be 100%.


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