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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

Getting started example of using 51Degrees device detection. The example shows how to:

  1. Set the data set for the 51Degrees detector

    string fileName = args[0];
    DataSet dataSet = StreamFactory.Create(fileName, false);
  2. Instantiate the 51Degrees device detection provider with these settings

    Provider provider = new Provider(dataSet);
  3. Produce a match for a single HTTP User-Agent

    match = provider.Match(userAgent);
  4. Extract the value of the IsMobile property

    IsMobile = match["IsMobile"].ToString();
This tutorial assumes you are building this from within the 51Degrees Visual Studio solution. Running the executable produced inside Visual Studio will ensure all the command line arguments are preset correctly. If you are running outside of Visual Studio, make sure to add the path to a 51Degrees data file as an argument.

Full Source File
        public static void Run(string fileName)
            // DataSet is the object used to interact with the data file.
            // StreamFactory creates Dataset with pool of binary readers to 
            // perform device lookup using file on disk. The type if 
            // disposable and is therefore contained in using block to 
            // ensure file handles and resources are freed.
            using (DataSet dataSet = StreamFactory.Create(fileName, false))
                // Provides access to device detection functions.
                Provider provider = new Provider(dataSet);

                // Used to store and access detection results.
                Match match;

                // Contains detection result for the IsMobile property.
                string IsMobile;

                // User-Agent string of an iPhone mobile device.
                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 version 41 on desktop.
                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.
                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/ " +

                Console.WriteLine("Staring Getting Started Example.");

                // Carries out a match for a mobile User-Agent.
                Console.WriteLine("\nMobile User-Agent: " + mobileUserAgent);
                match = provider.Match(mobileUserAgent);
                IsMobile = match["IsMobile"].ToString();
                Console.WriteLine("   IsMobile: " + IsMobile);

                // Carries out a match for a desktop User-Agent.
                Console.WriteLine("\nDesktop User-Agent: " + desktopUserAgent);
                match = provider.Match(desktopUserAgent);
                IsMobile = match["IsMobile"].ToString();
                Console.WriteLine("   IsMobile: " + IsMobile);

                // Carries out a match for a MediaHub User-Agent.
                Console.WriteLine("\nMediaHub User-Agent: " + mediaHubUserAgent);
                match = provider.Match(mediaHubUserAgent);
                IsMobile = match["IsMobile"].ToString();
                Console.WriteLine("   IsMobile: " + IsMobile);

                // Returns the number of profiles that are Mobile.
                Console.WriteLine("\nNumber of mobile profiles: {0}", 
                    dataSet.FindProfiles("IsMobile", "True").Length);

Full Source File

For more examples see the tutorials pages.


The .NET 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

To install the 51Degrees .NET API you should have Visual Studio. The project has been built and tested in Visual Studio 2013. To use this API you must be using .NET 4.0+