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.
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

With the recent announcement of delaying third-party cookie deprecation to 2024, the industry has more time to rethink how to identify and communicate with consumers.

As today’s digital landscape gets more and more complicated there are more ways for brands to connect with users and drive purchases and more ways for ad tech to target and measure those touch points. As in-person shopping picks up steam due to the re-normalization of society post-COVID 19; the connection between digital ads and in-person purchases needs to be made once again. With the rise of Connected TV throughout the pandemic there are even more digital opportunities to target a user. But how do you make sure that those brand engagements are captured and correctly attributed to offline purchases and conversions? The answer lies in a holistic identity resolution strategy. Cross-device identity resolution with The Tapad Graph connects the identifiers and devices of individuals within a household to each other; enabling targeting, frequency capping, extension, segmentation and measurement or attribution between devices; including Connected TV and hashed (privacy-protected) email addresses along with Cookies, Mobile Ad Ids and IP Address. Brands can join their first-party data to The Tapad Graph to execute strategies that connect online and offline data for pre, mid and post-campaign efficiencies. Let’s imagine a scenario in which an outdoor retail brand is targeting users watching specific content on a Connected TV device. Powered by identity resolution, they start with a general ad on CTV and continue targeting down individual paths with each user. When one of them converts in store and makes a purchase; the outdoor retailer can connect that action through location and in-store traffic data with the cross-device identity resolution used to execute the digital campaign. Now the actions of the user online and offline are resolved for more accurate measurement and attribution after the campaign ends. But it doesn’t stop there– the brand's CRM data can be reactivated for the next digital campaign and leveraged to capitalize on the most effective media mix for the user who made the purchase previously. These combined insights can be invaluable in shaping up future campaign strategies with geo-contextual ads, recommended additional products and personalization to help drive more conversions and purchases in-store or online. As in-person shopping picks back up and marketers are tasked once again with balancing online and in-store KPIs, the right identity resolution strategy can unlock necessary efficiencies for retailers, ad tech vendors and agencies tasked with supporting these initiatives. Get started with The Tapad Graph For personalized consultation on the value and benefits of The Tapad Graph for your business, email Sales@tapad.com today!

With Discovery Platform, you can find meaningful consumer insights and activate that data to reach growth audiences using content messaging that speaks to their motivations and interests. Take your marketing campaigns from audience discovery to media planning, execution and reporting.