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
We spoke with industry leaders from Ampersand, Basis Technologies, Captify, Cuebiq, CvE, Fetch, Madhive, MiQ, and Samsung to gather insights on how innovations in data and identity are creating stronger consumer connections. Here are five key insights to consider. 1. Build on trust with first-party data Stricter privacy regulations and growing customer expectations mean businesses must rethink how they gather and use data. A robust first-party data strategy centers on gathering high-quality data, such as behavioral and transactional data. By using behavioral, lifestyle, and purchasing data, brands can craft personalized strategies that align with their goals. This approach balances effective targeting with building trust and complying with privacy rules. Integrating identity solutions like Unified I.D. 2.0 (UID2) and ID5 into existing data strategies improves interoperability across platforms while keeping user privacy intact. These tools help create more effective campaigns. "We've been preparing and leaning into educating our clients around the value of first-party data. These are very important and primary considerations in any of our campaigns."April Weeks, Basis Technologies 2. Align metrics with business goals To demonstrate clear value, campaigns need to tie their outcomes to broader goals. Relying only on click-through rates or CPMs won’t cut it. Metrics that measure meaningful results, like driving sales or increasing customer retention, provide greater transparency than surface level data, like clicks or impressions. A continuous feedback loop between targeting and measurement ensures campaigns can be refined to better align with business objectives. This feedback helps marketers understand who they are targeting and how those audiences are driving key business results. Shifting focus to metrics that resonate with stakeholders ensures that marketing efforts are evaluated based on their true contribution to the company's objectives. "The television industry has access to more data than ever before, and at Samsung Ads, our ACR technology helps us provide valuable insights about what content and ads are being viewed. This abundance of data enables us to support clients in aligning their campaigns with business objectives effectively."Justin Evans, Samsung Ads 3. Personalize experiences to boost engagement Personalization drives stronger customer relationships by delivering tailored experiences to individual customer needs. Using data-driven insights to fine-tune offers and messaging makes interactions more relevant, strengthening brand loyalty. Combining behavioral, lifestyle, and transactional data provides a comprehensive understanding of the customer journey and ensures each touchpoint feels personal. Testing and iterating on personalization strategies also helps identify which data and approaches yield the best results. 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. Learn how Swiss Sense measured marketing outcomes using Mosaic® "We are playing a leading role in democratizing new tools for local advertisers. By mimicking the marketing funnel mentality, we've introduced solutions ranging from measuring brand lift to tracking foot traffic and app downloads."Luc Dumont, Madhive 5. Adapt quickly to stay competitive The only constant in advertising is change. Adapting quickly to new technologies and consumer behaviors keeps businesses competitive. A culture of agility fosters innovation, making it easier to respond to industry shifts and discover new opportunities. Companies that anticipate change and invest in modern data solutions position themselves for long-term growth. Whether it’s adjusting to privacy updates, exploring emerging tech, or staying flexible, businesses must continuously invest in adapting their platforms and strategies. "Falling behind is not really an option. There's always a change in advertising and in data where there's a new horizon. The people who stay close to that and innovate will always follow it."Amelia Waddington, Captify Shaping the future Building meaningful consumer connections requires advertisers to combine robust data strategies with flexibility and innovation. By focusing on these five considerations, marketers can adapt to today’s challenges while preparing for what’s ahead. Connect with our experts Latest posts
Experian’s 2025 Digital trends and predictions report offers insights from our industry-leading data and partners on 2025 marketing trends.