Why do I need ads.txt?

Ads.txt is meant to give buyers (DSPs and advertisers) a way to verify that the impression they are buying from an SSP is legitimately on your site, and not a fraudulent actor pretending to be your site. By authorizing a seller in your ads.txt, you are telling the buyer that they can, in fact, access your inventory through that pathway, and they can buy with confidence. To that end, you should list all available pathways in your ads.txt, otherwise some buyers may choose not to buy.

In general, for publishers, the importance of any ads.txt line is to gain access to more buyers and more advertising campaigns, thus driving yield.

Why do I need these DIRECT lines?

“Direct” in the context of ads.txt means that you have a direct relationship with the SSP — you have an account with them, and receive payment from them for the impressions they sell. If you work with Sortable seats, most SSPs still consider this a direct relationship with you, even though it is Sortable’s account. In this case, Sortable is acting as a network of publishers selling through the same account. If you can see an SSP listed as a partner in your Sortable Ad Revenue or Performance reports, they can be considered “direct”.

All SSPs and Exchanges require you to list their ads.txt line, to show that you have authorized them to sell your inventory. Not including a DIRECT line for an SSP means that that specific SSP will not be able to perform well — DSPs will be checking if they are authorized, and most will choose not to buy if the SSP’s line is not found in your ads.txt file. Some SSPs will decline to participate on your site altogether if their line is missing, because they know they will not be able to sell effectively.

Here is a recent example showing how participation for one SSP was unblocked when the publisher added the missing DIRECT ads.txt line:

Even if an SSP is not currently enabled on your site, we recommend that you include the DIRECT line we provide for them. This means the partner will be able to participate right away if and when we do enable them. It also allows you and the Sortable Success team to optimize your stack by easily testing different partners.

Why do I need multiple DIRECT lines for a single partner?

Sometimes Sortable has multiple accounts with a single SSP. We may have different accounts to access different demand products (for example, one for display and one for video). We may have different accounts for different kinds of connections (for example, one for header bidding and one for Google Open Bidding). Some SSPs may be migrating from one platform to another, and we need to keep accounts enabled in both systems during the transition. And as you know, projects don’t always go to plan. Some SSPs start a transition like this, and then never fully complete it. Some of their buyers continue buying through the old platform indefinitely, so we need to keep both accounts active to access all their buyers.

In some cases, even if you have your own relationship with a given SSP, we may ask you to add the DIRECT line for Sortable's account as well, in order to access demand formats or products that are available exclusively through Sortable's connection, such as Sponsored Video.

You need these ads.txt lines so that all of these pathways can perform well. Most DSPs and advertisers will not buy through pathways that are not authorized by your ads.txt, and you may simply lose out on this potential advertising spend. 

Note that including an ads.txt line is not the same as enabling a pathway or demand format. If you don’t have video demand enabled on your site, for example, adding a video-specific ads.txt line will not allow video to serve. It simply means that if you choose to test video demand, buyers will be able to participate as soon as we enable it, because this pathway is pre-authorized. Conversely, removing an ads.txt line will not necessarily prevent that partner from participating on your site. Be sure to engage with the Sortable Success team if you wish to enable or disable a partner so that we can include the correct bidders in your auction requests.

Why do I need these RESELLER lines?

In programmatic advertising, nothing is straightforward. There are often several actors in the “supply chain” connecting your inventory to an advertiser. When there are multiple SSPs in the chain, everything after the first, “direct”, connection is called a “reseller”. These resellers also need to be authorized in your ads.txt file. When Sortable asks you to add reseller lines, it is always because we believe these lines will allow an additional, unique revenue stream. 

A few SSPs and Exchanges view Sortable as a seller of your inventory, rather than a network. These partners ask us to use a RESELLER line, because in their view, they are reselling inventory they received from Sortable. In this case, the RESELLER line is required for this partner to participate and perform well, just like DIRECT lines above.

Many SSPs maintain accounts of their own with other SSPs and exchanges, in order to leverage features or capabilities of those other SSPs, rather than needing to build everything themselves. For example, this may be to serve formats that need specialized technology, like video or native, or it might be to access buyers in geographical areas that they can’t support on their own. These reseller accounts can also be used as a private marketplace, where the SSP you are directly connected to sources their own unique PMP deals. We ask that you add these RESELLER lines because these are campaigns and deals that are not otherwise available through your DIRECT lines.

For smaller publishers, RESELLER lines may also be valuable because they can allow you access to the full demand of an SSP or exchange that your site would otherwise not be approved for. Some SSPs restrict approvals based on metrics like monthly impression volumes or traffic history. Allowing your existing demand partners to resell through their own accounts with these SSPs can help you to access more advertising spend.

To help you interpret the ads.txt lines we provide you, we include a hashtagged comment at the end of every line, like this:

sovrn.com, 203268, DIRECT, fafdf38b16bf6b2b #Sovrn
rubiconproject.com, 17960, RESELLER, 0bfd66d529a55807 #Sovrn 

In this case, the first line is for Sortable's direct relationship with Sovrn. The second line shows that Sovrn can resell your inventory through Magnite (formerly known as Rubicon), a large exchange leveraged by many SSPs to flight deals and access a wider demand pool.

Is this too many lines?

We've heard concerns from publishers that adding too many ads.txt lines may open them up to malicious advertisers or other risks. Rest assured that Sortable thoroughly vets every demand source that we work with, and we review every ads.txt line provided to us by our demand partners to ensure that these lines are legitimate, trustworthy, and contributing unique value to your ad stack. Our Ad Quality team is continually monitoring to ensure our demand is safe.

If you need help interpreting or evaluating any of the ads.txt lines we've provided you with, reach out to the Sortable Success team for more information.

