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

Ensure you understand privacy compliance pitfalls with special attention on shopping cart abandonment emails.

Partnership combines customer connections and cross-device scale to deliver more strategic customer insights NEW YORK AND CHICAGO — March 16, 2017 — Signal, the global leader in customer identity, today announced a partnership with Tapad, now part of Experian and the leading provider of unified, cross-screen marketing technology solutions. This global integration extends device connectivity for Signal’s clients across North America, APAC and EMEA by leveraging Tapad’s proprietary Device GraphTM. With Signal’s Customer Identity Solution, brands benefit from more visibility of known customers, lower costs to reach those customers and decreased expenses and data loss that often results from using multiple vendors. Integrating with Tapad’s Device Graph, which connects billions of devices, enables Signal clients to build an even broader view of their known customers across multiple devices. This integration combines Signal’s customer identity scale with Tapad’s device scale to expand the reach of addressable media channels and enhance customer journey insights across touchpoints. Tapad and Signal were able to drive incremental device connections for more than 65 percent of customer profiles, linking an average of 6.8 browsers and devices per customer. With this combined data set, Signal clients can expand their authenticated view of a customer to all associated devices and realize more strategic insights into their high-value users. The partnership also allows Signal’s clients to integrate in real-time with Tapad’s media platform, Unify. This proprietary technology enables advertisers to make real-time activation and buying decisions with maximum scale, as well as automated reporting and measurement. “Continuously recognizing customers across devices instantly and in a privacy-safe way is essential for marketers to stay competitive,” said Marc Kiven, founder and CRO of Signal. “We are thrilled to enter this unique, global partnership with Tapad, enabling our clients to access their technology and more effectively reach customers in real-time and at scale.” “Being able to leverage a persistent view of customer connections across devices is a huge challenge for brands,” said Pierre Martensson, SVP and GM of Tapad’s global data division. “With Tapad, Signal is now able to connect with the billions of existing data points in our device graph to help clients better understand customer behavior and realize even stronger customer engagement.” Contact us today

Early successes include revenue increases, global partnerships and fundraising NEW YORK, March 16, 2017 /PRNewswire/ — Tapad's entrepreneurial mentorship initiative, the Propeller Program, has seen extremely positive results since it began in September 2016. The five early-stage startups selected from Norway have gained momentum in establishing a U.S. presence. Tapad, now a part of Experian, is the leader in unified cross-device marketing technology. The company was acquired by the Telenor Group in 2016. Among the successes within Propeller: Xeneta, the leading ocean freight price comparison platform and contracted rate database, has raised an additional $12M in funding since beginning the Propeller Program. Before the end of 2016, the company had exceeded its revenue expectations by nearly 30 percent, proving the European-focused business could succeed in the American market. "Aside from directly impacting our revenue, the Propeller Program has provided us with incredible access to a countless number of external resources, including subject matter experts from the fields of fundraising, public speaking, corporate structuring and immigration law," said William Di Ieso, GM of North America for Xeneta. "We remain extremely grateful for the opportunity and exposure the program has provided for Xeneta." Bubbly, an in-store real-time engagement tool for non-buyers, now has clients on four continents. After only a few months in the U.S. market, Bubbly has signed deals with one major retail brand, one major toy manufacturer and a major global consulting firm. The Propeller Program has also opened doors for greater opportunities in Scandinavia and EMEA. After an introduction to Telenor Group's President and CEO Sigve Brekke, Bubbly is currently piloting its IoT kiosk with the company. "The mentoring sessions have been very valuable and have given us guidance as to how to best enter the U.S. market," said Marianne Haugland Hindsgaul, Bubbly CEO and co-founder. "Learning to do business in the U.S. is not something you can necessarily learn from a book. The most impactful lessons are based on real-world experience, and that is what the Propeller Program has given us." BylineMe, a marketplace for freelancers, publishers and brands to connect for content creation and distribution services, has built an extensive network of potential clients and investors. The company has tested its product in the U.S. market and gained valuable feedback for further development. Eventum, a property-sharing group that digitally assists in securing venues for meetings and corporate events, has closed a seed round of funding for nearly $1M. Eventum has also made key hires in the areas of business development and engineering. Socius, under the influence of Tapad, pivoted into the ad tech space, positioning itself as "a social native ad platform" for digital publishers. The company has attracted top talent to begin building out its U.S. business development and sales divisions. As a result, Socius has signed a host of premium publisher partners to validate its exciting new direction. "It is so rewarding to be able to support these Norwegian startups in a meaningful way," said Are Traasdahl, CEO and founder at Tapad. "Mentor relationships are critical for strategic growth, and I am proud to be able to pay forward the experiences I have gained as an entrepreneur. To me, the Propeller Program is a shining example of the magic that can happen when Norwegian innovation meets American opportunity." Contact us today!