Client Hints are a set of HTTP headers and a JavaScript API that allow web browsers to send detailed information about the client device and browser to web servers.

userAgent

user-Agent

Client Hints JavaScript API

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Client Hints HTTP Headers

sec-ch-ua	loading...
sec-ch-ua-platform	loading...
sec-ch-ua-mobile	loading...
sec-ch-ua-full-version	loading...
sec-ch-ua-platform-version	loading...
sec-ch-ua-full-version-list	loading...
sec-ch-ua-arch	loading...
sec-ch-ua-bitness	loading...
sec-ch-ua-wow64	loading...
sec-ch-ua-model	loading...
sec-ch-save-data	loading...
sec-ch-width	loading...
sec-ch-viewport-width	loading...
viewport-width	loading...
sec-ch-viewport-height	loading...
sec-ch-dpr	loading...
dpr	loading...
sec-ch-device-memory	loading...
device-memory	loading...
sec-ch-rtt	loading...
sdownlink	loading...
sec-ch-ect	loading...
ect	loading...
sec-ch-prefers-color-scheme	loading...
sec-ch-prefers-reduced-motion	loading...
sec-ch-prefers-reduced-transparency	loading...
sec-ch-prefers-contrast	loading...
sec-ch-forced-colors	loading...
sec-ch-ua-form-factors	loading...

Known Client Hints List

```
Sec-CH-UA
```
Represents the brand and version of the user agent
```
Sec-CH-UA-Full-Version
```
Indicates the complete version of the user agent. (Deprecated, replaced by Sec-CH-UA-Full-Version-List)
```
Sec-CH-UA-Full-Version-List
```
Indicates the full version of the user agent (deprecated, replaced by Sec-CH-UA-Full-Version-List)
```
Sec-CH-UA-Platform
```
Represents the platform for a given user agent.
```
Sec-CH-UA-Platform-Version
```
Represents the platform version for a given user agent.
```
Sec-CH-UA-Arch
```
Represents the architecture of the platform for a given user agent.
```
Sec-CH-UA-Bitness
```
Indicates the bitness of the platform architecture on which the given user agent is executing
```
Sec-CH-UA-WoW64
```
Used to detect whether the user agent binary is running in 32-bit mode on 64-bit Windows.
```
Sec-CH-UA-Model
```
Represents the device executing the given user agent.
```
Sec-CH-UA-Mobile
```
Detects if the user agent is optimized for mobile user experience.
```
Sec-CH-UA-Form-Factors
```
Indicates the device form factor, historically represented by the deviceCompat token in User-Agent strings.
```
Sec-CH-Lang
```
(or Lang) Represents the user's language preference.
```
Sec-CH-Save-Data
```
(or Save-Data) Indicates the user agent's preference for reduced data usage.
```
Sec-CH-Width
```
Provides the layout width of images to the server.
```
Sec-CH-Viewport-Width
```
(or Viewport-Width) The width of the user's viewport in CSS pixels.
```
Sec-CH-Viewport-Height
```
Represents the current viewport height of the user agent.
```
Sec-CH-DPR
```
(or DPR) Reports the ratio of physical pixels to CSS pixels on the user's screen.
```
Sec-CH-Device-Memory
```
(or Device-Memory) Indicates the approximate amount of device memory in GiB. Because this information could be used to identify users, Device-Memory values are deliberately coarse. Valid values are 0.25, 0.5, 1, 2, 4, and 8.
```
Sec-CH-RTT
```
(or RTT) Provides the approximate round-trip time at the application layer, in milliseconds. This RTT includes server processing time and differs from transport-layer RTT. Values are rounded to the nearest 25ms to prevent fingerprinting.
```
Sec-CH-Downlink
```
(or Downlink) Represents the approximate downlink speed of the user's connection in megabits per second (Mbps). Values are rounded to the nearest multiple of 25 kilobits per second (kbps) to prevent fingerprinting.
```
Sec-CH-ECT
```
(or ECT) Stands for Effective Connection Type. Its value is one of an enumerated list of connection types, each describing a connection within a specified range of RTT and downlink values. Valid ECT values are '4g', '3g', '2g', and 'slow-2g'.
```
Sec-CH-Prefers-Color-Scheme
```
Indicates the user's preferred color scheme.
```
Sec-CH-Prefers-Reduced-Motion
```
Detects if the user has requested the system to minimize the amount of animation or motion it uses.
```
Sec-CH-Prefers-Reduced-Transparency
```
Detects if the user has requested the system to minimize the number of transparent or semi-transparent layer effects it uses.
```
Sec-CH-Prefers-Contrast
```
Detects if the user has requested web content to be presented with higher (or lower) contrast.
```
Sec-CH-Forced-Colors
```
Detects if the user agent has enabled forced colors mode, where it enforces a user-chosen limited color palette on the page.

Client Hints are a set of HTTP headers and a JavaScript API that allow web browsers to send detailed information about the client device and browser to web servers.

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