As an experienced C# (visual studio / .NET) programmer, I have successfully delivered numerous applications on time and within budget, many even involving WebAPIs similar to your project requirement. I feel confident in stating that I possess the skillset required to meet and exceed your expectations for this assignment.
Building sophisticated applications is second nature to me, precisely what you need here! I will program your two apps - one in console and another in Windows Forms- with utmost care, making sure the POST request execution is seamless while also taking care of state validations for errors. Be it sending, receiving or the error handling response display, my expertise with C#(like HttpClient and Task), ASP.NET Core will make everything smooth.
Above all, what sets me apart is my commitment to client satisfaction and my objective of completing projects quickly without compromising any quality. So, by choosing me for this project, you can rest assured that it would be in secure hands and delivered proficiently. My aim is to turn clients' dreams into functionality, and I'd be honored to do so for you with my robust C# skills! Let's connect and discuss the details further!