JSON .NET brings the power of Json and Bson serialization to Unity with support for 4.7.2 and up and is compatible with both .NET and IL2CPP backends.

Officially Supported Platforms We officially support all Unity platforms including WebGL, except for WebPlayer, Windows 8.0 and Windows Phone 8.0. Windows 8.1 is supported for 8.1 Universal on Unity 5 and above. If you have a special need for Windows 8.0, or Windows Phone 8.0/8.1 contact me and I can work on a special build.

Consoles are also supported! (Xbox360, Xbox One, PS3, PS4 and WiiU).

Note: GameObjects and MonoBehaviors cannot be serialized directly as well as some built in classes (such as Texture2D that doesn't have a public parameterless constructor) but they are simple to serialize using either proxy classes or creating a custom ContractResolver or JsonConverter. JSON .NET is super extensible.

Existing Customers Important: As this is a complete revamp, please backup and delete your existing /JsonDotNet folder before importing this package. Product Information
Official Company Website Tutorial
Release Thread

Highlights
Precompiled for faster builds
Full source code is included
Works with IL2CPP as Well as .NET Backend
Supports both JSON and BSON (binary) Serialization
Retains original JSON .NET namespaces
Supports Stripping down to ByteCode Level on both iOS and Android
Supports Micro Mscorlib on Android (but not iOS due to platform limitation).

JSON .NET for Unity retains the original namespaces and structure of the Newtonsoft Json.Net library with Unity supported features. This means that it will function as a drop-in replacement for the existing Json.Net dll for users who wish to target iOS and Web Player but need to use first class serialization. The current asset is based on JSON .NET 8.0.3 with additional official fixes and Unity specific functionality added.

JSON .NET For Unity