.NET Core 3 was recently released and brought with it a bunch of innovations. Besides C# 8 and support for WinForms & WPF, the new release added a brand new JSON (de)serializer. This new serializer goes by the name System.Text.Json and as the name suggests, all its classes are in that namespace.
Read more: https://michaelscodingspot.com/the-battle-of-c-to-json-serializers-in-net-core-3/
