Robotecture » HTTP » HTTP Headers » Sec-CH-UA-Platform

Sec-CH-UA-Platform HTTP Header: Overview

The Sec-CH-UA-Platform HTTP header is a user agent client hint request header that provides information about the platform or operating system on which the user agent is running. This header is a low entropy hint, which means that it is sent by default unless blocked by a user agent permission policy.

The purpose of the Sec-CH-UA-Platform HTTP header is to provide website owners with information about the platform or operating system that their visitors are using. This information can be used to optimize the website’s performance and user experience for specific platforms or operating systems.

The Sec-CH-UA-Platform HTTP header is just one of several user agent client hint headers that can be used to provide website owners with information about their visitors’ devices and browsers. By using these headers, website owners can gain valuable insights into their visitors’ preferences and behaviors, which can help them to improve their website’s performance and user experience.

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Why is the Sec-CH-UA-Platform HTTP Header important?

The Sec-CH-UA-Platform HTTP Header is an important security feature that helps to protect users from fraudulent activities and improve their overall experience. This section will explore the key reasons why the Sec-CH-UA-Platform HTTP Header is so important.

Enhancing Security

One of the most important reasons why the Sec-CH-UA-Platform HTTP Header is important is that it enhances security. By providing information about the platform or operating system on which the user agent is running, this header allows websites to better protect their users from potential security threats.

For example, if a website knows that a user is running Windows 10, it can take steps to ensure that the user is protected from any known vulnerabilities or security threats that might be specific to that platform. This can help to prevent hackers and other malicious actors from gaining access to sensitive information or causing other types of damage.

Preventing Fraudulent Activities

Another important reason why the Sec-CH-UA-Platform HTTP Header is important is that it can help to prevent fraudulent activities. By providing information about the platform or operating system on which the user agent is running, this header can help websites to detect and prevent fraudulent activities that might be specific to certain platforms.

For example, if a website knows that a user is running an older version of Android that is known to be vulnerable to certain types of attacks, it can take steps to prevent those attacks from occurring. This can help to protect users from fraud and other types of malicious activity.

Improving User Experience

Finally, the Sec-CH-UA-Platform HTTP Header is important because it can help to improve the overall user experience. By providing information about the platform or operating system on which the user agent is running, this header can help websites to optimize their content and user interface for different platforms.

For example, if a website knows that a user is running an iOS device, it can optimize its content and user interface to better suit that platform. This can help to improve the user experience and make it easier for users to navigate and interact with the website.

Overall, the Sec-CH-UA-Platform HTTP Header is an important security feature that helps to protect users from fraudulent activities and improve their overall experience. By providing information about the platform or operating system on which the user agent is running, this header allows websites to better protect their users and optimize their content and user interface for different platforms.

How does the Sec-CH-UA-Platform HTTP Header work?

The Sec-CH-UA-Platform HTTP header is a client hint request header that provides information about the platform or operating system on which the user agent is running. This header is a low-entropy hint, meaning that it does not reveal specific details about the user’s device or operating system. Unless blocked by a user agent permission policy, it is sent by default without the server opting in by sending Accept-CH.

When a user agent sends a request to a server, it includes the Sec-CH-UA-Platform header in the request headers. The server can then use this information to tailor its response to the user’s platform or operating system. For example, a website might use this information to serve a different version of the site to users on mobile devices versus desktop devices.

The following diagram shows the browser sending request headers to the server including the user agent string and receiving response headers including Accept-CH: sec-ch-ua-platform. During this initial request, the client will record the Accept-CH preferences and on subsequent requests include sec-ch-ua-platform by default.

It is important to note that the value of the Sec-CH-UA-Platform header can be spoofed or modified by the user agent or other software. Therefore, it should not be relied upon as the sole means of identifying a user’s platform or operating system. Instead, servers should use this header in conjunction with other techniques, such as feature detection, to ensure that their responses are appropriate for the user’s device.

Implementing the Sec-CH-UA-Platform HTTP Header

When implementing the Sec-CH-UA-Platform HTTP header, there are a few things to keep in mind. This header provides information about the platform or operating system on which the user agent is running. Here are some steps to follow when implementing this header:

Ensure that the website is being accessed over HTTPS. The Sec-CH-UA-Platform header is only available in secure contexts, so it will not work if the website is being accessed over HTTP.
Set up the server to request the Sec-CH-UA-Platform header by including the Accept-CH header in the response to any request from the client. Here is an example of how to do this:

HTTP/1.1 200 OK
Accept-CH: Sec-CH-UA-Platform

Once the server has requested the header, the client may choose to provide the hint and add the Sec-CH-UA-Platform header to subsequent requests. Here is an example of how to do this:

GET /example HTTP/1.1
Host: example.com
Sec-CH-UA-Platform: Windows

The header may include “fake” brands in any position and with any name. However, it is important to note that this is a low entropy hint, so it should not be relied upon for security purposes.