In 2022, Google began changing the availability of the information available in User-Agent strings across their Chromium browsers. The change is to use the set of HTTP request header fields called Client Hints. Through this process, a server can request, and if approved by the client, receive information that would have been previously freely available in the User-Agent string. This change is likely to have an impact on publishers across the open web that may use User-Agent information today.
To explain what this change means, how it will impact the AdTech industry, and what you can do to prepare, we spoke with Nate West, our Director of Product.
What is the difference between User-Agents and Client Hints?
A User-Agent (UA) is a string, or line of text, that identifies information about a web server’s browser and operating system. For example, it can indicate if a device is on Safari on a Mac or Chrome on Windows.
Here is an example UA string from a Mac laptop running Chrome:

To limit the passive fingerprinting of users, Google is reducing components of the UA strings in their Chromium browsers and introducing Client Hints. When there is a trusted relationship between first-party domain owners and third-party servers, Client Hints can be used to share the same data.
This transition began in early 2022 with bigger expected changes beginning in February 2023. You can see in the above example, Chrome/109.0.0.0, where browser version information is already no longer available from the UA string on this desktop Chrome browser.
How can you use User-Agent device attributes today?
UA string information can be used for a variety of reasons. It is a component in web servers that has been available for decades. In the AdTech space, it can be used in various ad targeting use cases. It can be used by publishers to better understand their audience. The shift to limit access and information shared is to prevent nefarious usage of the data.
What are the benefits of Client Hints?
By using Client Hints, a domain owner, or publisher, can manage access to data activity that occurs on their web properties. Having that control may be advantageous. The format of the information shared is also cleaner than parsing a string from User-Agents. Although, given that Client Hints are not the norm across all browsers, a long-term solution may be needed to manage UA strings and Client Hints.
An advantage of capturing and sharing Client Hint information is to be prepared and understand if there is any impact to your systems and processes. This will help with the currently planned transition by Google, but also should the full UA string become further restricted.
Who will be impacted by this change?
Publishers across the open web should lean in to understand this change and any potential impact to them. The programmatic ecosystem supporting real-time bidding (RTB) needs to continue pushing for adoption of OpenRTB 2.6, which supports the passing of client hint information in place of data from UA strings.
What is Google’s timeline for implementing Client Hints?

Do businesses have to implement Client Hints? What happens if they don’t?
Not capturing and sharing with trusted partners can impact capabilities in place today. Given Chromium browsers account for a sizable portion of web traffic, the impact will vary for each publisher and tech company in the ecosystem. I would assess how UA strings are in use today, where you may have security concerns or not, and look to get more information on how to maintain data sharing with trusted partners.
We can help you adopt Client Hints
Reach out to our Customer Success team at tapadcustomersuccess@experian.com to explore the best options to handle the User-Agent changes and implement Client Hints. As leaders in the AdTech space, we’re here to help you successfully make this transition. Together we can review the options available to put you and your team on the best path forward.
Get in touch
About our expert

Nate West, Director of Product
Nate West joined Experian in 2022 as the Director of Product for our identity graph. Nate focuses on making sure our partners maintain and grow identity resolution solutions today in an ever-changing future state. He has over a decade of experience working for media organizations and AdTech platforms.
Latest posts

NEW YORK, Oct. 16, 2019 /PRNewswire/ – Tapad, part of Experian and a global leader in digital identity resolution, and The Trade Desk, a global advertising technology leader, partnered to integrate The Trade Desk's unified ID solution in April 2019. The Trade Desk's unified ID solution's objective is to serve as a standardized cookie ID to help marketers reach more of their audience on the open internet. After an initial six month period, Tapad reports significant adoption rates and enhanced customer results since their joint integration in April. As a result of the partnership, client brands, agencies, DMPs/ DSPs, Data Providers, Mobile Networks and Measurement/Analytics Providers, saw increased match rates up to 38% and more global coverage without compromising precision. With this combined offering, Tapad's global, privacy-safe digital cross-device solution, The Tapad Graph, connects brands with consumers over 4 billion devices globally. Over 25 companies who license The Tapad Graph, such as Annalect, Semasio, Retargetly, and ThinkCX, have also included The Trade Desk's unified ID solution as a key identifier in their graph output. "The vast improvement in scale that Tapad has seen illustrates the value digital identity resolution products can bring for brands," said Nate Gawel, General Manager of Data Partnerships at The Trade Desk. "We're looking forward to continuing work with Tapad to prove that the open internet can deliver the very same benefits many reserve for large platforms." Adoption of the unified ID solution allows all parties across the supply chain (SSPs, DSPs, DMPs and data providers) to utilize The Trade Desk's cookie footprint to increase their own cookie coverage across the global independent internet. For more information, please visit The Trade Desk's unified ID solution site, or https://www.experian.com/marketing/consumer-sync to learn more about Tapad's digital identity resolution products. About Tapad:Tapad, Inc. is a global leader in digital identity resolution. The Tapad Graph, and its related solutions, provide a transparent, privacy-safe approach connecting brands to consumers through their devices globally. Our one-of-a-kind Graph Select offering enables marketers the flexibility and freedom of choice to correlate devices to varied objectives, driving campaign effectiveness and business results. Tapad is recognized across the industry for its product innovation, workplace culture and talent, and has earned numerous awards including One World Identity's 2019 Top 100 Influencers in Identity Award. Headquartered in New York, Tapad also has offices in Chicago, London, Oslo, Singapore and Tokyo. About The Trade Desk:The Trade Desk™ is a technology company that empowers buyers of advertising. Through its self-service, cloud-based platform, ad buyers can create, manage, and optimize digital advertising campaigns across ad formats and devices. Integrations with major data, inventory, and publisher partners ensure maximum reach and decisioning capabilities, and enterprise APIs enable custom development on top of the platform. Headquartered in Ventura, CA, The Trade Desk has offices across North America, Europe, and Asia Pacific. To learn more, visit thetradedesk.com or follow us on Facebook, Twitter, LinkedIn and YouTube. Contact us today

Gen Z is ready to be noticed and become a force to be reckoned with in the market. In the auto market alone, Gen Z made up 3.8 percent of all new vehicle registrations in the first quarter of 2019.

As ever, marketers have to be strategic to reach the right customers. Ensure seasonal messaging reaches the right customers with audience optimization.