FirstImpression estimates that among the top 30,000 publishers according to Alexa ranks, 16% of those using ads.txt have errors in their text files. Similarly, ads.txt validator AdAuth, which scanned 300,000 publishers, found that over 10% of websites using ads.txt have mistakes in their files.
Syntax errors represent some of the most common mistakes in ads.txt files. The ads.txt spec gives guidelines on how the required information—which includes the exchange’s domain, as well as the publisher’s account identification number and relationship to the exchange—should be ordered and laid out. Syntax errors can occur when publishers forget to include a space between each of these variables, leave out commas to separate the variables or place the information in the wrong the order.
“The data is unparseable because it fails to adhere to the basic syntax of the spec,” said Ian Trider, director of real-time bidding (RTB) operations at Centro, a DSP. “So DSPs will ignore such records, which would result in not bidding on the corresponding bid requests.”
Publishers also misspell the names of the vendors they work with and list invalid domains in their text files. Another common type of error is missing records, which happens when the required pieces of information that DSPs rely on when buying inventory are missing. All of these errors can lead a DSP to not bid on a publisher’s impressions that come through the particular vendor where the errors in the text file lie.