If we are talking about .net, I find it strange to create your own SDK client to use it for calling different services nowadays. Most of the APIs use Swagger by default, since it's the standard in Microsoft's point of view (it's "auto-added" when you create a new web api project since .net 5), so you can use different tools that generates the sdk client without you losing your resources to do it. I can give you an example of the oldest that I know which is nswag studio, but I've heard about WebApiClientGen and I'm pretty sure others are also ok.