title: How Does AWS CloudFront Detect Mobile Devices
body: <p>AWS CloudFront can detect the device type based on the value of the User-Agent header:</p>
  
  <blockquote>
    <p>If you want CloudFront to cache different versions of your objects
    based on the device a user is using to view your content, configure
    CloudFront to forward the applicable headers to your custom origin:</p>
    
    <ul>
    <li>CloudFront-Is-Desktop-Viewer</li>
    <li>CloudFront-Is-Mobile-Viewer</li>
    <li>CloudFront-Is-SmartTV-Viewer</li>
    <li>CloudFront-Is-Tablet-Viewer</li>
    </ul>
    
    <p>Based on the value of the User-Agent header, CloudFront sets the value
    of these headers to true or false before forwarding the request to
    your origin. If a device falls into more than one category, more than
    one value might be true. For example, for some tablet devices,
    CloudFront might set both CloudFront-Is-Mobile-Viewer and
    CloudFront-Is-Tablet-Viewer to true.</p>
  </blockquote>
  
  <p><a href="https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/header-caching.html#header-caching-web-device" rel="noreferrer">https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/header-caching.html#header-caching-web-device</a></p>
  
  <p>I'm wondering if AWS has published a list of user agents they use to detect mobile browsers. </p>
  
  <p>The documentation mentioned "If a device falls into more than one category", so I need to know how it determines these categories.</p>