JSON-RPC.NET
A high performance JSON-RPC 2.0 server for .NET. Bytes in, bytes out, so it hosts anywhere: Kestrel, a console app, sockets, pipes, or inside the browser as WebAssembly. The JSON serializer is pluggable; the core needs none.
On one core a small request takes about 250 ns with no allocation. Runs on .NET Framework 4.6.1 and up through .NET 10.
dotnet add package AustinHarris.JsonRpc