WIN32API

WinAPI (also known as Win32; officially called the Microsoft Windows API) is an application programming interface written in C by Microsoft to allow access to Windows features.

MSDN documentation

https://docs.microsoft.com/en-us/windows/win32/api/

MalAPI.io

MalAPI.io is a site that groups the various functions of the WinAPI depending on their use by malicious software. As a practical example, the CreateToolhelp32Snapshot function, used to take snapshots of running processes or modules on our Windows host, is mostly used for enumeration purposes, whereas the EncryptFileA function, used to encrypt files, is commonly found in ransomwares.