# Learn about user agent strings
<a name="user-agent"></a>

In the user agent request header field, Amazon Silk sends one of three user agent strings, depending on the view requested on the device by the customer. If a specific view is not requested, the view defaults to Tablet for Fire tablets, and Mobile for Fire phones. If a site has compatibility issues when rendered in the default view, a different view may be selected by the device. The templates for the Amazon Silk user agents are shown below.

**Tablet**

```
1. Mozilla/5.0 (Linux; Android {{android-version}}; {{product-model}} Build/{{product-build}}) AppleWebKit/{{webkit-version}} (KHTML, like Gecko) 
2.     Silk/{{browser-version}} like Chrome/{{chrome-version}} Safari/{{webkit-version}}
```

**Desktop**

```
1. Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/{{webkit-version}} (KHTML, like Gecko) 
2.     Silk/{{browser-version}} like Chrome/{{chrome-version}} Safari/{{webkit-version}}
```

**Mobile**

```
1. Mozilla/5.0 (Linux; Android {{android-version}}; {{product-model}} Build/{{product-build}}) AppleWebKit/{{webkit-version}} (KHTML, like Gecko) 
2.     Silk/{{browser-version}} like Chrome/{{chrome-version}} Mobile Safari/{{webkit-version}}
```

**Note**  
Red and italics indicates variable fields, which are described below.

**Template fields**
+ {{android-version}} – The [Android platform version](http://developer.android.com/about/dashboards/index.html) (for example, `4.4.3`).
+ {{product-model}} – The value of [Build.MODEL](http://developer.android.com/reference/android/os/Build.html#MODEL) (for example, `KFTT`).

  For a complete list of the product models, see [Learn about screen resolution](screen-size.md).
+ {{product-build}} – The value of [Build.ID](http://developer.android.com/reference/android/os/Build.html#ID) (for example, `IML74K`).
+ {{webkit-version}} – Indicates the version of WebKit used (for example, `535.19`). The version can change whenever the Fire device receives a software update.
+ {{browser-version}} – Indicates the version of the Amazon Silk browser (for example, `44.1.54`). The version can change whenever the Fire device receives a software update.
+ {{chrome-version}} – The version of Google Chrome with which the Amazon Silk browser is compatible.

## User agent string examples
<a name="examples"></a>

### Examples of the Amazon Silk User Agent String
<a name="ua_examples_latest"></a>

**Tablet**

```
Mozilla/5.0 (Linux; Android 4.4.3; KFTHWI Build/KTU84M) AppleWebKit/537.36 (KHTML, like Gecko) 
    Silk/44.1.54 like Chrome/44.0.2403.63 Safari/537.36
```

**Desktop**

```
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) 
    Silk/44.1.54 like Chrome/44.0.2403.63 Safari/537.36
```

**Mobile**

```
Mozilla/5.0 (Linux; U; Android 4.4.3; KFTHWI Build/KTU84M) AppleWebKit/537.36 (KHTML, like Gecko) 
    Silk/44.1.54 like Chrome/44.0.2403.63 Mobile Safari/537.36
```

### UA for Kindle Fire 1st Generation
<a name="ua_1stgen"></a>

**Note**  
The UA for the Kindle Fire 1st Generation follows a slightly different syntax. 

In the examples below, red and italic text indicates variable fields. The Amazon Silk-Accelerated value can be either `true` or `false`, depending upon customer selection.

**Desktop/Tablet**

```
1. Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_3; en-us; Silk/{{1.0.13.81_10003810}}) AppleWebKit/533.16 (KHTML, like Gecko) Version/5.0 Safari/533.16 Silk-Accelerated={{true}}
```

**Mobile**

```
1. Mozilla/5.0 (Linux; U; Android 2.3.4; en-us; Silk/{{1.0.13.81_10003810}}) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1 Silk-Accelerated={{true}}
```