2023 May 9: Support for Chrome User-Agent Client Hints

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Example 5. 2023 May 9: Support for Chrome User-Agent Client Hints

Adform now supports User-Agent Client Hints (UA-CH), an API solution developed by Google. It establishes a standard way to gather information about a visitor’s browser and device. By using UA-CH, publishers can access important browser information while maintaining visitor privacy. If you use User-Agent Client Hints, you make reliable data available for precise technical targeting in advertisers’ campaigns.

Google introduced User-Agent Client Hints (UA-CH) with Chrome 83, released in May 2020. UA-CH provides a standard and privacy-preserving way for obtaining information about a visitor’s browser and device.

The User-Agent string is a standard header that website servers use to identify the visitor’s browser and operating system. However, the User-Agent string includes additional details about the visitor’s device which potentially could compromise user privacy. Because of the lack of standardization in the User-Agent string among browsers, website servers can’t reliably parse and extract relevant information. This can cause incorrect or incomplete device identification. Therefore, Google developed an alternative solution, UA-CH. The UA-CH header helps website owners access each visitor’s device information in the User-Agent string in a more standardized and privacy-preserving way.

User-Agent strings have long been used in programmatic advertising to provide insights. For publishers, the User-Agent string provides information about how browsers, operating systems, and devices render their website content, as well as how visitors interact with the publisher’s websites. Publishers can use this data to optimize their ad placements and customize visitors’ experiences. For example, publishers can customize their website content based on a visitor's location, country, or language. Advertisers can use the data captured by a User-Agent string to target specific audiences based on the device type, operating system, and browser. This ensures that their ads reach the intended audience.

How UA-CH Works

With UA-CH, the website server requests specific information from the browser about the capabilities and preferences of the visitor's device. When the browser receives such a request, it sends a response based on its own policies. Instead of exposing the entire User-Agent string by default on all requests, the browser passes only essential device-related information.

What Action is Required?

  • Publishers: To access detailed and accurate information about a visitor’s device, you must implement the UA-CH header in all your websites that parse User-Agent strings. For information on how to set up UA-CH, see our Help article.

  • Advertisers and agencies: Contact the publishers that you work with and verify whether they've implemented UA-CH on their websites. Once the UA-CH is implemented, Adform can make reliable data available for precise technical targeting.

  • Site-Tracking clients: Adform Site Tracking relies on the User-Agent string for precise page visit recording in retargeting campaigns. To ensure the effectiveness of this process, you must implement UA-CH on websites that use Adform Site Tracking. For information on how to implement UA-CH, see our Help article.

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