I would highly suggest using an already developed and tested library for OAuth, if you are able to. It not only saves time and eliminates the possibility of subtle bugs, but it leaves your code smaller, and you can focus more on the actual integration, rather than the authentication. If you want to build it yourself, though, I have used these references before to build authentication for C# and PowerShell, though it took a bit of time and testing to get it just right: https://oauth.net/core/1.0/ https://tools.ietf.org/html/rfc5849