*** IMPORTANT CHANGE IN RESTSHARP VERSION 103 *** In 103.0, JSON.NET was removed as a dependency. If this is still installed in your project and no other libraries depend on it you may remove it from your installed packages. There is one breaking change: the default Json*Serializer* is no longer compatible with Json.NET. To use Json.NET for serialization, copy the code from https://github.com/restsharp/RestSharp/blob/86b31f9adf049d7fb821de8279154f41a17b36f7/RestSharp/Serializers/JsonSerializer.cs and register it with your client: var client = new RestClient(); client.JsonSerializer = new YourCustomSerializer(); The default Json*Deserializer* is mostly compatible, but it does not support all features which Json.NET has (like the ability to support a custom [JsonConverter] by decorating a certain property with an attribute). If you need these features, you must take care of the deserialization yourself to get it working. If you run into any compatibility issues with deserialization, please report it to http://groups.google.com/group/restsharp