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Guidelines for CTV/OTT Device and App Identification

By Amit Shetty

With the growth of Connected TV (CTV), Set Top Boxes, and other Over-The-Top (OTT) devices, and the explosion in streaming video services, the OTT space is fast becoming one of the most important segments of video advertising. With this growth comes many technical challenges. The wide range of CTV/OTT devices that support streaming have a variety of hardware, software and, therefore, varying capabilities. This diversity has caused significant complications for processes that were generally straightforward in mobile and desktop digital video environments.

In the past, the IAB Tech Lab’s OTT Technical Working Group and Digital Video Working Group have worked to address these issues. The “Guidelines for OTT Identifier for Advertising (IFA)” was released in 2018, and the VAST4.x  specs have been updated with best practices for ad delivery and measurement when using Server-Side-Ad-Insertion (SSAI).

Here, the OTT Technical Working Group is calling attention to two other challenges that have been highlighted in recent discussions – inconsistencies in how we use “app identifiers” and challenges with the use of user agents to determine device types.

     1. App Identifiers 

Unique app identifiers within OTT inventory are crucial for buyers, first and foremost, as a way of knowing which apps they are buying ad placements on, but also in targeting, blacklisting, brand safety, and fraud prevention. In the same way that domains can be used to identify and understand web traffic, buyers need a standardized way to identify and understand app traffic. Identifying the app correctly is also very important in anti-fraud initiatives like app-ads.txt. However, as we have learned from the mobile world, there can be inconsistencies caused by the use of the non-unique identifiers. In addition, lack of guidelines as well as OTT device fragmentation have caused confusion in the OTT/CTV app space.

In order to address this, the OTT Technical Working Group recommends the use of the “app store IDs” where available. We also provide direction on how to communicate this in OpenRTB and VAST. A more detailed discussion of the problem and guidance is available to download here.

      2.   User Agents 

Accurate device information, such as type, Operating System (OS), and client software, is crucial in the advertising ecosystem. It allows for precise targeting, better creative delivery, analytics and measurement. Today, according to our members, a large number of impressions on CTV devices are incorrectly reported as not CTV, making buyers question the campaign validity and sometimes denying publishers of proper credit for their inventory.

The primary reason behind this problem is that there is no reliable technology to identify the device type independently. The only standard facility that transports device and client software information is User-Agent HTTP request header, and that solution has a number of gaps.

In order to address this, the OTT Technical Working Group has recommended a usable structure for the User Agent string that device platforms should provide, as well as recommendations for additional methods that can be used to mitigate the problem. For a more detailed discussion of the problematic user agents as well as the recommendations, please download the guidance here.

There are a number of other challenges that we are working on in the OTT Technical Working group, such as how verification should work on OTT devices and updates to the AdCOM object model to better support video/OTT inventory. We welcome everyone to join our working group and add to these conversations.

Note – we are aware that the terms OTT and CTV have been used interchangeably even though they have differences and overlaps. The guidance above is intended for all internet connected devices that are connected to (or part of) a television set and not intended for mobile and desktop inventory.


Amit Shetty
Senior Director, Video & Audio Products