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.
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In a perfect world, we’d all have a single, go-to grocery store that carried everything on our shopping list – fresh produce, gourmet coffee beans, rare spices, and maybe even that special-grade olive oil, right alongside our wholesale bulk purchases at unbeatable prices. It would be convenient and efficient, and it’d save a lot of driving around town. The changing data marketplace: From one-stop shop to specialized selection For a long time, data buyers enjoyed something similar in their world: a small set of large-scale data marketplaces that offered a wide array of audiences, making it easy to load up on whatever you needed in one place. Not only are there fewer places to pick everything up, but new factors like privacy and signal deprecation are placing a spotlight on quality and addressability. Just as our dinner plans are growing more ambitious insofar as we want health, flavor, value, and convenience all in one place – so are our data strategies. 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Data buyers aren’t just thinking about broad scale; they’re looking to prioritize quality, durability, data privacy, and differentiation. They need to place higher value on data marketplaces that can maintain audience addressability over time, despite signal loss. Sometimes, that means accepting a smaller assortment in exchange for tighter vetting and more reliable targeting. Other times it means mixing and matching – stopping by one marketplace for premium segments and another for cost-friendly, wide-reaching data sets. Either way, they can benefit from having more choices. “Experian has been a longstanding partner of DISH Media, and we’re excited to be an early adopter of their marketplace which leverages the foundation of their identity solutions to ensure maximum cross-channel reach as we look to expand the breadth and depth of data we use for addressable TV.”Kemal Bokhari, Head of Data, Measurement & Analytics, DISH Media Experian’s marketplace: A trusted source for high-quality data Experian’s vetted and curated blend of data partners and vertically-aligned audiences offers a trusted specialty store for data buyers. Experian’s marketplace, powered by identity graphs that include 126 million households, 250 million individuals, and 4 billion active digital IDs, enables partner audiences to be easily activated and maintain high addressability across display, mobile, and connected TV (CTV) channels. In particular, Experian’s marketplace provides: Enhanced addressability and match rates All audiences delivered from the marketplace benefit from our best-in-class offline and digital identity graphs, which ensure addressability across all channels like display, mobile, and CTV. Unlike other data marketplaces, Experian ensures all identifiers associated with an audience have been active and are targetable, improving the accuracy of audience planning. Enhanced addressability and match rates All audiences delivered from the marketplace benefit from our best-in-class offline and digital identity graphs, which ensure addressability across all channels like display, mobile, and CTV. Unlike other data marketplaces, Experian ensures all identifiers associated with an audience have been active and are targetable, improving the accuracy of audience planning. Enhanced addressability and match rates All audiences delivered from the marketplace benefit from our best-in-class offline and digital identity graphs, which ensure addressability across all channels like display, mobile, and CTV. Unlike other data marketplaces, Experian ensures all identifiers associated with an audience have been active and are targetable, improving the accuracy of audience planning. The future of data marketplaces: Precision and flexibility matter The evolution of data marketplaces reflects the industry's shifting priorities. Data buyers seek specificity, reliability, and adaptability to align with their diverse campaign needs. The best data strategy, much like the best grocery run, isn’t about grabbing everything in one place – it’s about carefully selecting the right ingredients to create the perfect recipe for success. This shift underscores the importance of flexibility and precision as data buyers navigate a landscape shaped by privacy regulations, signal loss, and evolving consumer expectations. As data marketplaces adapt to meet these demands, they are redefining what it means to deliver value. Experian’s marketplace enables buyers to strike the perfect balance between reach and quality by offering enhanced match rates, precise audience planning, and seamless distribution. In this new era, data buyers have the tools and options to craft campaigns that are impactful and aligned with the increasingly selective and privacy-conscious digital landscape. The key is recognizing that today’s data strategy is about utilizing the strengths of many to create a cohesive and effective whole. If you're interested in learning more about Experian's marketplace or becoming an active buyer or seller in our marketplace, please contact us. Contact us Latest posts

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Scaling these efforts means customers receive the right messaging at the right time, and businesses see better outcomes. "Every business should be building a data strategy that thinks about the different versions of data that exist and how they bring that together. They don't necessarily need to own all of it but have a clear rationale and strategy about where you're using which data sets."Paul Frampton, CvE 4. Utilize advanced measurement tools for smarter decisions Improving the effectiveness of campaigns starts with using sophisticated measurement tools to gain actionable insights. Using analytics like brand lift studies, foot traffic analysis, app download tracking, incrementality, and share of search allows marketers to understand the full impact of their efforts. With these resources, teams can pinpoint what’s working, make real-time adjustments, and refine their approach. This adaptability ensures budgets are used as effectively as possible. 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