Newtonsoft is a software company known for its development of high-quality JSON frameworks for .NET. The company is most recognized for its popular product, Json.NET, which is widely used in the .NET ecosystem for handling JSON data. This powerful library offers robust capabilities for serializing and deserializing JSON, making it a staple for developers working with JSON in .NET applications. Additionally, Newtonsoft provides a variety of related products and resources for developers through their online store at https://www.newtonsoft.com/store, where users can explore and purchase tools to enhance their development projects.