What is ads.txt?
Ads.txt stands for "Authorized Digital Sellers". AdSpirit was part of the team, which created and defined the rules for this. It is a mechanism on how a publisher/website owner can tell potential buyers that the traffic they are buying is valid. It also tells the buyer that the SSP/DSP from which they are receiving the traffic is wanted/allowed by the publisher. This prevents third parties ("ad-frauders") to send traffic to buyers and claim that the traffic originates from your website (by falsifying the referrer domain in the bid-request). See more info on the IAB page: https://iabtechlab.com/ads-txt/
How does ads.txt work?
In order to allow advertisers to check if traffic that is offered via RTB is valid, the advertiser can check the ads.txt file of the offered domain. Therefore the publisher needs to upload a text file called "ads.txt" on its domain, so it is accessible via http(s)://publisherdomainname.com/ads.txt. The file includes a list of all direct partners and resellers that are allowed to sell traffic for this domain. If a buyer is receiving traffic for this domain from a different SSP/DSP than whats in the list, the advertiser will know that it might be fraud traffic.
In order to locate the app-ads.txt file two things are necessary: The app bundle or app id and the Appstore URL of the app. The appstore will then publish the app's website and the app-ads.txt file can be found under the same domain https://appdomain.com/app-ads.txt.
How does the ads.txt file look like?
The file is a simple text file which can look like this:
#this is ads.txt for domain example.com
mydsppartnerA.com,123,DIRECT
mydsppartnerB.com,456,RESELLER,ha9n21j
myssppartnerC.com,789,DIRECT
Basically the file includes one record per line and each reacord is separated by comma into fields. One record consists of the domain-name of the partner SSP/DSP which is allowed to sell the traffic. The second field of the record is the publisher-ID (OpenRTB field publisher.id) for which the publisher will be visible to buyers within this DSP/SSP. The third field is either the word "DIRECT" or "RESELLER". This signals the type of account or relatiohship from publisher to SSP/DSP. An optional fourth field gives a certification authority ID (e.g. TAGID).
I'm a Publisher: How to setup my own ads.txt file?
In order to setup your own ads.txt file, simply create a textfile using Notepad/Edit or similar software and save it as ads.txt on your website so it becomes accessible via yourdomainname.com/ads.txt. In order to fill the file, please ask your partners (SSP, DSP, Exchanges, Networks, ...) for the ads.txt records for you.
If a publisher does not want or cannot maintain the ads.txt file on his website, he can also setup a 302 HTTP redirect to a different ads.txt file (e.g. the ads.txt of the SSP).
I'm a SSP/Exchange/Network: How shall my publishers setup their ads.txt file?
In order to validate the traffic that you are selling to your clients, you need to ask your publishers to implement the ads.txt file on their website. The file should include a record that points to your adserver domain:
#adserverdomain,website-id,DIRECT
mycompany.adspirit.de,123,DIRECT
The first field of the record is your AdSpirit adserver domain (usually companyname.adspirit.de). The second field in the record is the website-ID of this website in your adserver. The third field is either the word "DIRECT" or "REDIRECT" - use "DIRECT" if you are a SSP and have direct access to the publishers page and bill directly with him; otherwise use "RESELLER". If a publisher uses more than one website in your adserver but all websites point to the same domain, please add one record (line) per website to the ads.txt file:
mycompany.adspirit.de,123,DIRECT
mycompany.adspirit.de,456,DIRECT
mycompany.adspirit.de,678,DIRECT
If a publisher does not want or cannot maintain the ads.txt file on his website, he can also setup a 302 HTTP redirect to a different ads.txt file (e.g. the ads.txt of the SSP).
I'm a DSP/TradingDesk/Advertiser: How can i verify the traffic?
Due to the fact that ads.txt is relatively new and most publishers did not yet implement it, AdSpirit does not yet offer an automated way on validating incoming traffic via ads.txt. This might change in the future.