Throttling and rate-limiting allow you to prevent abuse of your API and ensure that your API withstands large numbers of calls (including DoS and accidental loops). With Throttling, you can set a delay on calls after an SLA tier has been exceeded, slowing down the number of requests an API client is making.

Overview

JSON Web Tokens is an emerging standard. They are very close to their standardisation. IETF has taken care of that, and OpenID connect mandates the use of JSON Web token for all of the tokens that are exchanged in that protocol. this article gives you a little look, an overview of the purpose of security tokens, and, and what other types of tokens we have out there and where, where they are used. Then we have a look at the structure of a JSON Web Token, and then we’ll show you how easy it is to create and consume them using the Microsoft DotNet Core development framework.

Here is a simple REST Client talking to a stand along Server API all written in DotNet Core 3.1.

It is loosely based on creating a simple REST Client, an tutorial from Microsoft can give you the very basic features in DotNet Core

https://docs.microsoft.com/en-us/dotnet/csharp/tutorials/console-webapiclient