HTTP Headers
Sec CH UA Full Version List
HTTP Header
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The HTTP Sec-CH-UA-Full-Version-List request header is a user agent client hint which provides the user-agent’s branding and full version information.
The Sec-CH-UA-Full-Version-List header provides the brand and full version information for each brand associated with the browser, in a comma-separated list.
The header may include “fake” brands in any position and with any name.
This is a feature designed to prevent servers from rejecting unknown user agents outright, forcing user agents to lie about their brand identity.
Note:
This is similar to Sec-CH-UA, but includes the full version number instead of the significant version number for each brand.
| Header type | Request header, Client hint |
|---|---|
| Forbidden request header | Yes (Sec- prefix) |
Syntax
A comma-separated list of brands in the user agent brand list, along with their corresponding complete version numbers.
The format for a single entry is structured as follows:
http
Sec-CH-UA-Full-Version-List: "<brand>";v="<full version>", ...
Directives
Directives
<brand>A brand associated with the user agent, like “Chromium”, “Google Chrome”.
This may be an intentionally incorrect brand like" Not A;Brand"or"(Not(A:Brand"(the actual value is expected to change over time and be unpredictable).<full version>A full version number, such as 98.0.4750.0.
Example
<strong>Description</strong></h2>A brand refers to a commercial name associated with a user agent, such as: Chromium, Opera, Google Chrome, Microsoft Edge, Firefox, and Safari.<br> A user agent can have multiple associated brands.<br> For example, Opera, Chrome, and Edge are all built on Chromium and will provide both brands in the Sec-CH-UA-Full-Version-List header.
<br> <p>This header enables servers to tailor their responses based on shared brands and specific customizations for each build.
</div>
<strong>Examples</strong></h2></div> <p>The header is requested by the server through the inclusion of the <strong>Accept-CH</strong> header in response to any client request, specifying the desired header name as a token:</p> <br> <div class="code-example"> <div class="example-header"><span class="language-name">http</span></div> <pre class="brush: http notranslate"><code>HTTP/1.1 200 OK<br>Accept-CH: Sec-CH-UA-Full-Version-List<br></code>></pre> </div> <p>The client can then choose to provide this hint by including the <code>Sec-CH-UA-Full-Version-List</code> header in subsequent requests, as shown below:</p> <br> <div class="code-example"> <div class="example-header"><span class="language-name">http</span></div> <pre class="brush: http notranslate"><code>GET /my/page HTTP/1.1<br>Host: example.site<br><br>Sec-CH-UA: " Not A;Brand";v="99", "Chromium";v="98", "Google Chrome";v="98"><br>Sec-CH-UA-Mobile: ?0<br>Sec-CH-UA-Full-Version-List: " Not A;Brand";v="99.0.0.0", "Chromium";v="98.0.4750.0", "Google Chrome";v="98.0.4750.0">&br>Sec-CH-UA-Platform: "Linux"></code>></pre> </div>
How to Modify Header using Requestly
Requestly is a handy tool that can also help you modify the Sec-CH-UA-Full-Version-List header, which carries detailed browser version info. Changing this header is useful when you want to test how your website or API responds to different browser versions or to debug compatibility issues. Steps to Modify the Sec-CH-UA-Full-Version-List Header:- Install and open the Requestly Chrome extension. You can find it on the Chrome Web Store.
- Create a new rule: Click on “Create Rule” and choose “Modify Headers” from the list of available rule types.
- Add a new header modification:
- Under “Action”, select “Add” or “Override”.
- In the “Header Name” field, enter Sec-CH-UA-Full-Version-List.
- In the “Header Value” field, enter the desired browser version string (e.g., “Chromium”;v=”110.0.5481.179″, “Google Chrome”;v=”110.0.5481.179″).
- Set the URL condition: Specify the URL or pattern where this header change should apply (e.g., https://your-website.com/*).
- Save the rule.
After completing these steps, Requestly will modify the Sec-CH-UA-Full-Version-List header in outgoing requests matching the URL pattern, allowing you to simulate requests from different browser versions for testing or debugging purposes.
A brand refers to a commercial name associated with a user agent, such as: Chromium, Opera, Google Chrome, Microsoft Edge, Firefox, and Safari.<br> A user agent can have multiple associated brands.<br> For example, Opera, Chrome, and Edge are all built on Chromium and will provide both brands in the Sec-CH-UA-Full-Version-List header.
<br> <p>This header enables servers to tailor their responses based on shared brands and specific customizations for each build.
</div>
<strong>Examples</strong></h2></div> <p>The header is requested by the server through the inclusion of the <strong>Accept-CH</strong> header in response to any client request, specifying the desired header name as a token:</p> <br> <div class="code-example"> <div class="example-header"><span class="language-name">http</span></div> <pre class="brush: http notranslate"><code>HTTP/1.1 200 OK<br>Accept-CH: Sec-CH-UA-Full-Version-List<br></code>></pre> </div> <p>The client can then choose to provide this hint by including the <code>Sec-CH-UA-Full-Version-List</code> header in subsequent requests, as shown below:</p> <br> <div class="code-example"> <div class="example-header"><span class="language-name">http</span></div> <pre class="brush: http notranslate"><code>GET /my/page HTTP/1.1<br>Host: example.site<br><br>Sec-CH-UA: " Not A;Brand";v="99", "Chromium";v="98", "Google Chrome";v="98"><br>Sec-CH-UA-Mobile: ?0<br>Sec-CH-UA-Full-Version-List: " Not A;Brand";v="99.0.0.0", "Chromium";v="98.0.4750.0", "Google Chrome";v="98.0.4750.0">&br>Sec-CH-UA-Platform: "Linux"></code>></pre> </div>
How to Modify Header using Requestly
Requestly is a handy tool that can also help you modify the Sec-CH-UA-Full-Version-List header, which carries detailed browser version info. Changing this header is useful when you want to test how your website or API responds to different browser versions or to debug compatibility issues. Steps to Modify the Sec-CH-UA-Full-Version-List Header:
- Install and open the Requestly Chrome extension. You can find it on the Chrome Web Store.
- Create a new rule: Click on “Create Rule” and choose “Modify Headers” from the list of available rule types.
- Add a new header modification:
- Under “Action”, select “Add” or “Override”.
- In the “Header Name” field, enter Sec-CH-UA-Full-Version-List.
- In the “Header Value” field, enter the desired browser version string (e.g., “Chromium”;v=”110.0.5481.179″, “Google Chrome”;v=”110.0.5481.179″).
- Set the URL condition: Specify the URL or pattern where this header change should apply (e.g., https://your-website.com/*).
- Save the rule.
After completing these steps, Requestly will modify the Sec-CH-UA-Full-Version-List header in outgoing requests matching the URL pattern, allowing you to simulate requests from different browser versions for testing or debugging purposes.
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