ads.txt (Authorized Digital Sellers) is a project by the IAB (Interactive Advertising Bureau) to try and eliminate the sale of counterfeit inventory (or arbitrage inventory) and domain spoofing.

As a new industry standard in the digital ad ecosystem, it's crucial that all publishers create and integrate an ads.txt file to prevent any loss of revenue, strengthen the integrity of their brand, and promote transparency in programmatic advertising.

For more information on ads.txt, see this article from Google. 

Why it's important

From mid-October 2017, Google and all other buyers started not buying inventory on sites that don't have or include all the correct providers on their ads.txt. 

Just as important, it's also a concentrated effort to protect a publisher's brand by reducing counterfeit inventory. Counterfeit inventory is where inventory is sourced from a domain and mislabeled on purpose to for example, sell invalid traffic or bypass content or domain blacklists. 

A complete and accurate ads.txt also ensures that advertisers are buying a publisher's actual inventory and not fraudulent spaces from a spoofed domain. Domain spoofing is when third-parties imitate a site and trick demand providers into buying inventory using the publisher's brand. For example, in this Digiday article, the Financial Times estimated that $1.3 million of spoofed ad space is sold each month.

How it works

Ads.txt is a basic text file that lists all the demand providers a publisher (seller) has authorized to buy or resell their inventory.  

The file is served in the publisher's root level of their domain. It must be posted there by the publisher's webmaster and is essentially a publicly accessible record.

The file specifically contains the following information for each demand provider (seller) the publisher uses in their ad configuration:

<SSP/Exchange domain>, <Your publisher ID for that provider>, <The seller's relationship with the publisher (DIRECT or RESELLER>, <The tag ID which is optional>

Marfeel's ads.txt

Marfeel's ads.txt is the following. The reason there are so many providers is a result of Marfeel's sophisticated ad setup that leverages competition among providers to maximize the value and return of a publisher's inventory: 

The list can also be downloaded in .txt format here:

ads.txt info

EMXDigital (Client + S2S), 137, RESELLER, 1e1d41537f7cad7f, 1356, RESELLER, f5ab79cb980f11d1

Index, 184550, RESELLER

Index (EBDA), 186442, RESELLER

Index (S2S), 187012, RESELLER

Google DFP, pub-3733785150938669, RESELLER, f08c47fec0942fa0

Google ADX, pub-2117324400584663, RESELLER, f08c47fec0942fa0

Pulsepoint, 560011, RESELLER, 89ff185a4c4e857c, 560444, RESELLER, 89ff185a4c4e857c, 560782, RESELLER, 89ff185a4c4e857c, 560783, RESELLER, 89ff185a4c4e857c, 560938, RESELLER, 89ff185a4c4e857c, 560939, RESELLER, 89ff185a4c4e857c

Sovrn, 243540, RESELLER , fafdf38b16bf6b2b, 243540, RESELLER, fafdf38b16bf6b2b, 11645, RESELLER, ffdef49475d318a9, 537120960, RESELLER, 83499, RESELLER, 538959099, RESELLER, 137711, RESELLER, 156700, RESELLER, 156212, RESELLER, 62483, RESELLER, 558511, RESELLER

Sovrn (EBDA), 247572, RESELLER, fafdf38b16bf6b2b, 243540, RESELLER, fafdf38b16bf6b2b, 1360, RESELLER, f5ab79cb980f11d1, 539924617, RESELLER, 6a698e2ec38604c6, 17960, RESELLER, 0bfd66d529a55807, 243540-eb, DIRECT, fafdf38b16bf6b2b

Smart,3005,RESELLER,560288,RESELLER,89ff185a4c4e857c,156439,RESELLER,154037,RESELLER,16114,RESELLER,0bfd66d529a55807,537149888,RESELLER,6a698e2ec38604c6,3703,RESELLER,f5ab79cb980f11d1, 101760, RESELLER, 3fd707be9c4527c3, s-2411, RESELLER, 6c8d5f95897a5a3b, 5679, RESELLER, 6c8d5f95897a5a3bx, 958, RESELLER, 81cbf0a75a5e0e9a, 2564526802, RESELLER, a670c89d4a324e47, 1100044045, RESELLER, 07bcf65f187117b4, 1006576, RESELLER, d641df8625486a7b, b4bf4fdd9b0b915f746f6747ff432bde, RESELLER


Rubicon (EBDA), 17990, DIRECT, 0bfd66d529a55807

Pubmatic, 155979, Reseller, 5d62403b186f2ace

Pubmatic (S2S), 156785, Reseller,5d62403b186f2ace

Pubmatic (EBDA), 157138, Reseller, 5d62403b186f2ace

Openx, 539639517, DIRECT, 6a698e2ec38604c6

Openx (EBDA), 539708242, DIRECT, 6a698e2ec38604c6

OpenX (S2S), 540611310,  DIRECT,  6a698e2ec38604c6

Appnexus, 9140, RESELLER, f5ab79cb980f11d1

E-Planning,41e0bb8d773dffe7,DIRECT,156631,RESELLER,5d62403b186f2ace,12186,RESELLER,0bfd66d529a55807,1767353092,RESELLER,a670c89d4a324e47, 1002, DIRECT, 190243, DIRECT

Amazaon, 713b5f85-602b-49d9-a3b8-33750c16a4fc, DIRECT, 540191398, RESELLER, 6a698e2ec38604c6, 157150, RESELLER, 5d62403b186f2ace, 100962, RESELLER, 1908, RESELLER, f5ab79cb980f11d1, 18020, RESELLER, 0bfd66d529a55807, 1654642120, RESELLER, a670c89d4a324e47, 12068, RESELLER, e1a5b5b6e3255540

Spotx, 170031, RESELLER, 7842df1d2fe2db34, 170031, RESELLER, 7842df1d2fe2db34

Sonobi, 1d7065c722, DIRECT, d1a215d9eb5aee9e, 1059622079, RESELLER, a670c89d4a324e47, 560606, RESELLER, 89ff185a4c4e857c

DistrictM (Mbid), 101887, DIRECT, 3fd707be9c4527c3, 1908, RESELLER, f5ab79cb980f11d1, pub-9685734445476814, RESELLER, f08c47fec0942fa0

Improve Digital (EBDA), 1364, DIRECT

Improve Digital (Client+S2S), 1534, DIRECT

Teads, 9887, DIRECT, 15a9c44f6d26cbe1

RhythmOne,4135307405,DIRECT,a670c89d4a324e47, 4135307405, DIRECT

You can also download the list of Marfeel's authorized providers directly here:

Marfeel Ads.txt.rtf

The demand providers then use crawlers to find and integrate ads.txt files in their platforms to confirm that they are buying and reselling the inventory they are authorized to buy or resell. This allows bidders to ensure that the publisher and demand provider have an authentic connection and that they are not buying inventory from a fake domain or buying counterfeit inventory.

Implementation steps

  1. If you already have an ads.txt file, copy and paste the above list of Marfeel authorized providers from and including #marfeel 010818 to your file and re-upload it. 
  2. If you don't have an ads.txt: 
    1. Download the above .txt file.
    2. Add all the other providers you use for desktop and mobile starting at #your ad configuration, following the same format. 

    3. Upload the file to the root level of your domain (ie. similar to your robots.txt file that instructs robots on how to crawl your site.