“Crawlers, Generators and Validators,” A Guide to the Ads.txt Tools Online

The IAB’s ads.txt initiative is a straightforward way for publishers to signal which exchanges and SSPs are authorised to sell their inventory. The initiative is seen by many as a win-win for all legitimate actors on both the buy-side and sell-side, with the only real downside being the time and resources it takes to set up or monitor. Thankfully there are plenty of tools available online to make the process as easy as possible, here we’ve picked out some of the most useful:

Ads.txt File Generators

Publishers wanting to use ads.txt simply need host a text file on their domain which lists all authorised sellers of their inventory. The address for this file should be whatever the publisher’s root domain is, with ‘/ads.txt’ added onto the end (e.g, example.com would host its ads.txt files at example.com/ads.txt).

The format for ads.txt is outline in the IAB’s specification so publishers can manually write the file themselves, but there are several ads.txt file generators which make the process easier. They tend to work similarly, crawling your domain to pull out a list of partnered sellers which can be modified before generating the file, but they each yield different results, so some might work better for your domain than others.


In order to assess whether a bid request for a piece of inventory is genuine, an advertiser needs to be able to see that publication’s ads.txt file and check if the seller presenting the bid request is listed there. Crawlers trawl through publications and return their ads.txt files, allowing this data to be integrated into the bidding process, filtering out illegitimate reselling. IAB has released its own sample crawler, but other options are available which add more functionality.


Errors in your ads.txt files can be hard to spot, but can lead to legitimate sellers not being recognised. These validators will flag up any help correct mistakes, helping to avoid lost sales.


  • Ads.txt Finder: An extension for Google Chrome which instantly flags whether a website is or isn’t running ads.txt, and gives you a quick way to view the files.
  • FirstImpression.io Industry Dashboard: Lays out the state of ads.txt adoption across the industry, showing which markets and sellers where adoption rates are highest.
  • Ads.txt Normalisation Mappings: An IAB database of all known ad system domain values, useful for correcting misspellings and mistakes within ads.txt files.
  • Ads.txt Plus: An extension of ads.txt, created by MetaX and available in beta, which brings ads.txt to the Ethereum blockchain.

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