Check out the latest documentation.


These pages show you how to set up and use the 51Degrees device detection API. For more information on how device detection works and can benefit you, please visit our Device Detection Page . If you’re using our cloud based device detection, you should refer to the Cloud API Documentation pages . All source code, and the free Lite data, is licensed under the Mozilla Public License version 2 .

Get Going With Our Tutorials

Full Source File
    // Device detection provider which takes User-Agents and returns matches.
    protected final Provider provider;
    // User-Agent string of a iPhone mobile device.
    protected final String mobileUserAgent = "Mozilla/5.0 (iPhone; CPU iPhone "
            + "OS 7_1 like Mac OS X) AppleWebKit/537.51.2 (KHTML, like Gecko) "
            + "Version/7.0 Mobile/11D167 Safari/9537.53";
    // User-Agent string of Firefox Web browser of version 41 used on desktop.
    protected final String desktopUserAgent = "Mozilla/5.0 (Windows NT 6.3; "
            + "WOW64; rv:41.0) Gecko/20100101 Firefox/41.0";
    // User-Agent string of a MediaHub device.
    protected final String mediaHubUserAgent = "Mozilla/5.0 (Linux; Android 4.4"
            + ".2; X7 Quad Core Build/KOT49H) AppleWebKit/537.36 (KHTML, like "
            + "Gecko) Version/4.0 Chrome/ Safari/537.36";
     * Initialises the device detection Provider with the included Lite data
     * file. For more data see: 
     * <a href="">compare data options
     * </a>
     * @throws IOException can be thrown if there is a problem reading from the 
     * provided data file.
    public GettingStarted() throws IOException {
        provider = new Provider(StreamFactory.create(
                Shared.getLitePatternV32(), false));
     * Matches provided User-Agent string and returns IsMobile property value.
     * Detection initiated by invoking {@link Provider#match(java.lang.String)}.
     * Detection results are then stored in the {@link Match} object and can be 
     * accessed using the {@code Match.getValues("PropertyName")} method.
     * @param userAgent HTTP User-Agent string.
     * @return String with value for IsMobile property for a given User-Agent.
     * @throws IOException if there is a problem accessing the data file.
    public String detect(String userAgent) throws IOException {
        Match match = provider.match(userAgent);
        return match.getValues("IsMobile").toString();
     * Main entry point for this example. For each of the User-Agents defined 
     * in this class: 
     * <ol>
     * <li>invokes {@link #detect(java.lang.String)} method; and
     * <li>prints results.
     * </ol>
     * Result in this case will be either True or False, depending on whether 
     * the User-Agent belongs to a mobile device or a non-mobile device.
     * @param args command line arguments, not used.
     * @throws if there is a problem accessing the data file 
     * that will be used for device detection.
    public static void main(String[] args) throws IOException {
        System.out.println("Starting GettingStarted example.");
        GettingStarted gs = new GettingStarted();
        try {
            System.out.println("Mobile User-Agent: " + gs.mobileUserAgent);
            System.out.println("IsMobile: " + gs.detect(gs.mobileUserAgent));
            System.out.println("Desktop User-Agent: " + gs.desktopUserAgent);
            System.out.println("IsMobile: " + gs.detect(gs.desktopUserAgent));
            System.out.println("MediaHub User-Agent: " + gs.mediaHubUserAgent);
            System.out.println("IsMobile: " + gs.detect(gs.mediaHubUserAgent));
        } finally {
     * Closes the {@link} by releasing data 
     * file readers and freeing the data file from locks. This method should 
     * only be used when the {@code Dataset} is no longer required, i.e. when 
     * device detection functionality is no longer required, or the data file 
     * needs to be freed.
     * @throws IOException if there is a problem accessing the data file.
    public void close() throws IOException {

Full Source File

For more examples see the Tutorials section.


The Java API is capable of operating in two modes: Stream and Memory.

Mode Description
Memory In memory mode the API will load the entire data file into memory as either a byte array or the set of entities. Memory mode is considerably faster than stream mode but requires significantly more main memory.
Stream In stream mode the API will only load data file headers and indexes of the entities. Stream mode is very memory efficient and has an extremely fast startup time whilst still delivering fast detections. Stream mode should be fast enough for most purposes.

How Does Device Detection Work?

51Degrees device detection implementation does not rely on regular expressions, instead our algorithm looks at character positions in the HTTP User-Agent string and picks a set of signatures that represents the closest match. Then a set of four profiles (one for each of the following components: hardware, software, browser and crawler) is derived from those signatures. Properties and the corresponding values are then derived from those profiles. For more information and examples please see the How Device Detection Works  page.

Premium and Enterprise data files can benefit from automatic update capabilities. If you're a Lite user you can contact us for a free evaluation to experience the benefits of automatic updates and check out the  extra properties and features that come with Premium and Enterprise data files.

The latest Premium and Enterprise data files can be obtained from the downloads area.

Prerequisites and Compatibility

The source code is compatible with Java versions 1.6+ (1.7+ if using Automatic Updates)