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

Experian Marketing Services and Data Quality President Genevieve Juillard recently sat down with Zach Rodgers, host of the AdExchanger Talks podcast to discuss the future of identity, the importance of data transparency and privacy, and our recent acquisition of Tapad. Genevieve focused on the opportunity for our industry to reimagine an advertising ecosystem that is resilient and adaptable; one that takes advantage of emerging data and prioritizes data transparency and consumer privacy. She also discussed the importance of advertising strategies that put consumers at the heart of every decision and give them more control over their data. Genevieve shared with AdExchanger that Experian’s acquisition of Tapad, a global leader in digital identity resolution, was a natural fit for our company. Tapad’s approach and role in the ecosystem is very much aligned with Experian’s, which is to develop solutions that are resilient to industry and consumer changes. The combination of our capabilities supports interoperability across all types of identifiers, both online and offline, and will position us to help our clients navigate the post-third-party cookie world. To learn more about Experian’s plans to support an effective advertising ecosystem that will evolve with our dynamic industry, listen to the full podcast Embracing ‘Healthy Fragmentation’ In Ad Tech, With Genevieve Juillard. Get in touch

It’s been over a year since Google announced they’d be deprecating the third-party cookie and in that time there’s been a major focus on two types of cookieless identity solutions. Identity vendors and marketers are strategizing which of these two future solutions best fits their needs so they can achieve privacy-safe scale once third-party cookies are no longer available for use on Chrome. Let’s break down these solutions and the considerations marketers need to take into account when deciding what partners to move forward with in the future of identity resolution. Authenticated Traffic Solutions Authenticated traffic solutions (ATS) are a type of digital identification that asks the end-user to identify themselves via personal information, most commonly email address. Often, you’ll see self-authentication at the point of entry to a website that asks you to create an account or login immediately to access the content you are seeking. E-commerce sites use authentication to keep track of consumer purchases and inform advertising decisions for that customer; and publishers use it to tailor featured content, or, more importantly for this discussion, leverage it within the ad ecosystem for targeting. While authentication can provide very valuable user data for audience segmenting and targeting, it can be limited in scale for a single publisher to leverage and monetize on their own. That’s why some identity vendors have worked to integrate themselves within as many publisher authentication modules as possible, so that they can create an aggregate of scale for the ad ecosystem to tap into. But, even this isn’t going to deliver the reach marketers truly thirst for. Alternatively, Facebook has the scale for authenticated traffic, but they keep their data inside a walled garden, so the utility of those authenticated users is only valuable within the Facebook ecosystem. So how can authenticated traffic solutions increase scale to broaden the scope of identifiers they can collect and leverage? Hint: a few of the biggest players have already figured it out. It’s the single sign-on. Google is probably the largest purveyor of a single-sign on solution that can directly impact advertising capabilities. Can you think of a site you visit that doesn’t offer a sign-in with your existing Google account? It’s a short list. Google has integrated themselves into so many applications and publishers that “Login with Gmail” is just second nature (you pictured the Gmail logo when you read that, didn’t you?). Now, if you’re about to purchase something you found off an Instagram ad, or perhaps a retailer you buy from regularly, you’ve probably noticed options to proceed with your checkout via “Amazon pay” or “Apple pay”. These are also single-sign ons. You’re authenticating yourself through Amazon or Apple to that retailer in exchange for A- the safety and security that Amazon or Apple provide for your financial information and B- skipping the annoying process of manually entering personal information over and over again at point of sale. It’s starting to sound like there’s a lot of authenticated data out there isn’t it? Well, that’s true, but again, Amazon and Apple are walled gardens. Amazon is working diligently to build out their own ecosystem to leverage their content and retail channel data for a holistic offering. And Apple keeps user data very close to the chest, constantly limiting its utility for themselves and advertisers. So what is identity resolution doing about it? The Trade Desk announced their solution; Unified ID 2.0, which promises to leverage email authenticated identity for a truly scaled solution for publishers via Javascript through Prebid. By handing over UID2.0 to an independent unbiased organization like Prebid, The Trade Desk is creating instant scale and trust in their solution. Unauthenticated Traffic Solutions Unlike ATS, unauthenticated traffic solutions do not rely on a log-in to identify a user, but they also don’t rely on third-party cookies. Instead, unauthenticated solutions (UATS) leverage their existing streams of real-time data through Javascript on publisher sites or an SDK (software development kit used by apps). The type of information UATS solutions can collect via Javascript or SDK vary, but it can include IP address, user agent and device level info. But being able to read this information at the point of entry to a website does not make a quality identifier. The best unauthenticated solutions will have the ability to set or ingest this information into a unique ID through an infrastructure with incredibly fast speed that can process trillions of anonymous data signals across multiple channels and devices. And even more so, be able to interpret those signals into a profile using machine learning– all at the moment a user enters a domain. It sounds complicated because it is, but it also has a lot of potential. The identity space cannot rest solely on authenticated traffic solutions, because, as you can see, it could limit ownership and operability to just a few power players/walled gardens. This doesn’t help the larger ecosystem monetize and personalize ad inventory. The right unauthenticated solution, however, can unify cross-device individuals and households at scale, because they’re integrated on the broadest number of publishers/SDKs across platforms, have the best algorithms to build confident connections between identifiers, and are universally transactable across the most common sell and demand side platforms. Think of it as the perfect partner- speaking a common language that everyone in the ecosystem understands and acts on. Today more than twenty cookieless identifiers are available in market for the ad ecosystem, and Google hasn’t even announced a date of deprecation. It’s important to be on the lookout for differentiators like scale and precision. Most importantly, choosing a truly cross-device partner will be key, especially as more digital devices and IDs grow in adoption, like CTV has this past year. Taking advantage of both What we will come to find, once the third-party cookie is obsolete, is that choosing just one of these solution types, or partners, will be a disadvantage. The more the industry comes together to collaborate on solutions, the more apparent it is that both of them have value, and thus employing both solutions will give marketers the best opportunities. Tapad, now part of Experian, recently announced the launch of Switchboard; a module within our identity solution; The Tapad Graph, to create this agnostic interoperability for identifiers of all types, and choice and control for the ad tech vendors and marketers who want them. By instantly creating the ability to partner with multiple solutions, Tapad + Experian is ensuring that all use cases for the third-party cookie live on in our cookieless future. Get in touch

Tapad launches global privacy-safe solution to provide continuity in the absence of third-party cookies Switchboard, a module within The Tapad Graph, will connect emerging cookieless identifiers to traditional IDs, creating a more holistic view of the consumer and driving value exchange within the advertising ecosystem Tapad, part of Experian, a global leader in cross-device digital identity resolution, and a part of Experian, announced today the launch of Switchboard, a first-of-its-kind solution to help navigate the evolving cookieless landscape. Switchboard, a module within The Tapad Graph, will operate as a global, privacy-safe solution to provide continuity in the absence of third-party cookies by connecting new cookieless identifiers to traditional digital IDs for a comprehensive view of consumers and their digital touchpoints. Switchboard will enable interoperability across the growing number of these digital identifiers and the value exchange between publishers, content creators and consumers. Leading digital identity solutions partnering with Tapad, part of Experian at the launch of Switchboard include Unified ID 2.0, ID5, Lotame Panorama ID, BritePool, Retargetly IDx and Audigent Halo ID. Tapad, part of Experian plans to expand support to additional identity solutions on an ongoing basis. In addition to these identity solutions, early partners across the ecosystem include The Trade Desk, Amobee, Martin, ShareThis, Eyeota and Catalina. “This diverse group of launch partners and testing customers will prove that Switchboard is an important tenet for the future of identity resolution. We’re excited to be proactive in our approach to give marketers time to adapt new solutions and test their function in tandem with the third-party cookie, while continuing to give our customers flexibility and control,” said Mark Connon, General Manager of Tapad, part of Experian. “Facilitating access and usage of 1st party identifiers is crucial to help marketers prepare for the cookieless future. Thanks to Switchboard, ID5's cookieless IDs will be available to a wider audience of brands and agencies and enable them to run effective, data-driven campaigns beyond the third-party cookie,” said Mathieu Roche Co-founder & CEO of ID5. Switchboard provides value across the marketing and advertising ecosystem as the need for the ability to support multiple cookieless ID’s across ad tech increases throughout 2021. With a decade of expertise creating digital identity resolution products, Tapad, part of Experian is poised to solve this challenge through innovation and quality, privacy-safe data-driven solutions. “Interoperability is paramount for brand marketers, agencies, publishers and platforms if we want to support an open and free Internet and break free of the stranglehold of walled gardens,” said Pierre Diennet, Global Partnerships at Lotame. ”Lotame Panorama ID’s participation in Switchboard reflects our steadfast commitment to collaborating across and within the industry and providing value to all of its players.” “As advertisers continue to contemplate the future of identity, Amobee is proud to partner with Tapad, part of Experian on this next-generation solution to provide a comprehensive view of consumers,” says Bryan Everett, Senior Vice President of Global Business Development at Amobee. “With the imminent loss of cookies, advertisers must think creatively in order to respectfully engage consumers in a privacy-compliant way and Switchboard can play an important role in addressing their respective identity needs.” Tapad, part of Experian is welcoming identity solutions and Tapad Graph customer participation in Switchboard throughout 2021. Stayed tuned for more updates and information on Switchboard in the coming months. Get in touch