CTV advertising is, without doubt, having a moment, its data-driven capabilities expanding the ‘one-to-many’ broadcast option offered by traditional TV so that targeted content can be delivered to multiple audiences. At the same time, a combination of regulatory, technical and industry factors mean CTV lacks the same safeguards as web and mobile, and buyers are understandably cautious. Here, we outline the issues and provide details of two IAB standards designed to address them.
Global CTV ad revenue is forecast to reach $46.3 billion in 2026. But despite this very positive projection and the clear benefits of the channel, some issues have still emerged.
CTV falls between broadcast and digital channels, making regulation challenging. This is exacerbated by the well-known issue of fragmentation. With CTV delivered across a range of apps, platforms, and devices, universal controls are difficult to apply. Meanwhile, the rapid adoption of the channel means its infrastructure is comparatively immature, so the industry is still playing catch-up when it comes to best practice.
Fraud is a major concern. CTV’s success, along with the high premium CTV inventory usually commands, has made it a honeypot for bad actors seeking to exploit vulnerabilities in the system. Common tactics include bot traffic, device and app spoofing, domain spoofing and Server-Side Ad Insertion (SSAI) spoofing, which all trick advertisers into paying for impressions that are fake, low quality, or simply not seen. Ad stacking and pixel stuffing inflate impression counts, while geographic misrepresentation sees fraudsters mislead buyers into believing ads are delivered to high-value audiences. Made For Advertising (MFA) CTV apps created to serve ads rather than provide genuine content have also become an increasingly large problem.
CTV’s opaque supply chain is another concern, with several culprits responsible for the lack of transparency. Fragmentation sees inventory spread across many sources, including smart TV manufacturers, streaming platforms, virtual MVPDs (Multichannel Video Program Distributors such as YouTube TV), device makers, and app developers. The non-unified infrastructure leads to multiple intermediaries (SSPs, resellers, OEM platforms) between buyer and seller, while reselling (multiple SSPs selling the same impression) and arbitrage (impressions bought low and sold high) add to the complexity. Visibility for advertisers is further restricted by many big CTV players operating walled gardens.
Another limiting factor is the low availability of contextual signals. There is no industry-wide standard for categorizing CTV content, making it difficult to target specific shows or genres by context. Inventory is often bundled, or sold through private marketplaces and direct deals, with inconsistent ‘packaging’ limiting insight on context. From a technical standpoint, much of the CTV ecosystem is built on legacy broadcast systems or fragmented digital platforms and integrating new contextual targeting is arduous. And although contextual targeting is regarded as privacy-friendly, the uncertainty of how privacy regulations will develop makes players hesitant to invest heavily.
As with every hurdle it has been presented with, the adtech industry is committed to addressing the complex nature of CTV advertising and the unique challenges it presents. The IAB standards app-ads.txt and OpenRTB 2.6 serve different purposes; brought together they tackle the barriers listed above with the aim of building trust in the channel. They ensure advertisers can invest in CTV with confidence, making them key tools for SSPs.
Let’s look at both in more detail.
The premise of app-ads.txt – or Authorized Sellers for Apps to give its full name - is straightforward.
Tailoring the original built-for-websites ads.txt to the specifics of mobile and CTV apps, the app owner or publisher creates and hosts a text file that lists all SSPs, resellers and ad exchanges authorized to sell their inventory.
This publicly available text file lists the authorized seller and related information such as their domain, publisher account ID, and whether they have a direct or reseller relationship. When a CTV viewer triggers a bid request to be sent out, buyers can verify via this file that the entity offering the inventory is approved by the publisher and reject sellers that are not listed.
Authorized sellers warrant a listing, while anyone unapproved does not. This transparency, which means buyers know who they are trading with, helps to develop the trust that has mainly been lacking to date. By making it easy to work only with authorized, direct sources, app-ads.txt also allows advertisers and DSPs to streamline their supply paths, ultimately improving performance and return on investment.
The public listing makes it much harder for bad actors to sell counterfeit inventory so buyers can’t be tricked into bidding on fake impressions. And, by blocking unauthorized intermediaries, app.ad.txt reduces arbitrage.
But of course, it’s not quite that simple.
The first problem is a practical one. App-ads.txt relies on the authorized seller listing being hosted on a publicly accessible website, but this is hampered by many CTV app developers and streaming apps operating without a traditional web domain (often because they work mainly through app stores and the ecosystems of streaming devices) making it difficult for buyers to determine whether a seller is legitimate.
Secondly, it’s back to the fragmentation issue. CTV content can be distributed through multiple channels, with each partner having the right to sell inventory. The resulting scenario, in which more than one party is a legitimate seller for the same content, is not covered by a single app-ads.txt file and requires the content owner, plus each distributor, to declare each other’s rights to sell inventory.
inventorypartnerdomain, now part of the app-ads.txt specification, has been designed to address the complexities of CTV inventory sharing. It brings transparency to the relationship between content owners and distribution partners by allowing each party to list the other as an authorized seller in their respective app-ads.txt files. The distributor must also declare the content owner in the bid request, ensuring the entire supply chain is visible and verifiable during transactions.
Increasingly, DSPs are actively checking published app-ads.txt files to verify that supply partners are authorized to sell the inventory for which they are sending bid requests. This filtering activity makes it critical that legitimate SSPs demonstrate their compliance and commitment to transparency by adopting it.
OpenRTB 2.6 introduced key changes to the way bid requests are managed, particularly for CTV. Specific upgrades are dynamic ad pods, channel / genre signals, SSAI indicators, and by-the-second pricing.
Ad pods are bundles of ads that run consecutively, similar to traditional TV ad breaks. Structured ad pods have a fixed number of ads, each with specified lengths; however, because slots are filled individually, buyers don’t have full visibility of the entire pod, making ad duplication a risk, along with a lack of competitive separation. This act of pod splitting, or the practice of filling one 90-second ad pod with multiple 30-second or even 15-second creative assets, contributes to a CTV bid request multiplication phenomenon, flooding the bidstream with duplicate CTV requests. This causes the supply chain to have to process more bid requests than needed. Dynamic ad pods, however, allow bid requests to include the duration of the complete commercial break, meaning buyers can respond with any combination of ad lengths to fill it.
This visibility enables frequency management, thereby avoiding the viewer bête noire of seeing the same ad multiple times. It’s also a win for brand safety as competing brands won’t appear in the same pod, while bidding is more efficient thanks to multiple slots being bundled into a single request. Buyers can fill pods in the way that makes the most sense to them, maximizing buyer response based on the CPM per second. And because publishers can attribute different values to each slot, buyers can select their preferred options, so bidding is more granular and competitive.
The Content Channel and Content Network fields in OpenRTB 2.6 allow publishers to include details on channel, network and genre in the bid request. This pre-bid transparency allows buyers to avoid ads appearing alongside unsuitable or risky programming. And in addressing the lack of contextual insight outlined above, these signals enable buyers to target inventory on a contextual basis, reducing wasted ad spend by making it more relevant and effective.
As noted above, SSAI spoofing is a tactic deployed by fraudsters. By adding the SSAI field to the bid request, OpenRTB 2.6 allows publishers to specify whether ad stitching (the technology that creates a seamless viewing experience) and measurement beacons originate from the client or server side. This transparency provides buyers with insight on how impressions are counted (thus avoiding billing discrepancies), and a means to detect anomalies that indicate potential fraud or invalid traffic (for example if a publisher claims that beacons are client-side, but billing notifications come from a server or data center).
Traditional pricing sees CPM floors apply a static price to each ad slot, regardless of its length. In contrast, OpenRTB 2.6 refines this method by introducing the mincpmpersec field, whereby publishers can establish a minimum acceptable price for every second of ad airtime within a pod. Moving away from a one-size-fits-all approach means that price floors accurately reflect the value of different ad lengths; longer ads command higher prices so publisher revenue is maximized, shorter ads are priced lower, so buyers can optimize efficiency, knowing that the ad price reflects its duration.
This checklist illustrates why SSPs that implement OpenRTB 2.6 make their CTV inventory supply significantly more attractive to DSPs and buyers, as well as easier to activate. In a competitive landscape, adopting this standard is a sound business decision.
A core tenet of BidSwitch’s rationale is to enable partners to trade seamlessly, with all parties realizing benefits; as such, we support OpenRTB 2.6 and can implement the new fields for CTV trading including pod structures and contextual metadata.
The same principle also sees us endorse app-ads.txt, and we help buyers evaluate the authenticity of inventory in real-time so that CTV advertising delivers on its promise.
We recommend that SSPs work with their CTV publishers to provide app-ads.txt files; these should include authorized sellers, be updated regularly and reflect shared monetization as relevant.
We also advise SSPs to support OpenRTB 2.6 bid fields through their platform to bring the benefits of ad podding, contextual data, SSAI transparency and more granular pricing floors.
The BidSwitch team is on hand to offer advice, practical setup assistance and implementation support. SSPs that want to know more about introducing these two standards to their CTV trading should contact their BidSwitch Account Manager.