diff --git a/csharp/src/Google.Protobuf.JsonDump/Program.cs b/csharp/src/Google.Protobuf.JsonDump/Program.cs
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+++ b/csharp/src/Google.Protobuf.JsonDump/Program.cs
@@ -0,0 +1,72 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+using System;
+using System.IO;
+
+namespace Google.Protobuf.ProtoDump
+{
+    /// <summary>
+    /// Small utility to load a binary message and dump it in JSON format.
+    /// </summary>
+    internal class Program
+    {
+        private static int Main(string[] args)
+        {
+            if (args.Length != 2)
+            {
+                Console.Error.WriteLine("Usage: Google.Protobuf.JsonDump <descriptor type name> <input data>");
+                Console.Error.WriteLine("The descriptor type name is the fully-qualified message name,");
+                Console.Error.WriteLine("including assembly e.g. ProjectNamespace.Message,Company.Project");
+                return 1;
+            }
+            Type type = Type.GetType(args[0]);
+            if (type == null)
+            {
+                Console.Error.WriteLine("Unable to load type {0}.", args[0]);
+                return 1;
+            }
+            if (!typeof(IMessage).IsAssignableFrom(type))
+            {
+                Console.Error.WriteLine("Type {0} doesn't implement IMessage.", args[0]);
+                return 1;
+            }
+            IMessage message = (IMessage) Activator.CreateInstance(type);
+            using (var input = File.OpenRead(args[1]))
+            {
+                message.MergeFrom(input);
+            }
+            Console.WriteLine(message);
+            return 0;
+        }
+    }
+}
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