Postman - The Collaboration Platform for API Development
Microsoft Research Detours - Detours is a software package for re-routing Win32 APIs underneath applications.
Insomnia REST - The most intuitive cross-platform REST API Client ð´
EasyHook - The reinvention of Windows API Hooking
soapUI - SoapUI Pro is one of the most prominent API testing platforms around, allowing developers to quickly prototype the functions of their apps and get them to market with little hassle.
WinAPIOverride - WinAPIOverride : This software allows you to monitor and/or modify any function of a process for any calling convention (stdcall or cdecl)