Nuklear
A single-header ANSI C gui library
...It is designed to be lightweight, portable, and self-contained, requiring no external dependencies. The library is easy to integrate into existing applications by including a single header file, making it popular for game development, prototypes, and embedded systems. Nuklear supports a variety of UI elements such as windows, buttons, sliders, and text inputs, with customizable styling for flexibility. Its immediate-mode design emphasizes simplicity and low memory usage, enabling developers to create responsive interfaces with minimal overhead. As a public domain project, Nuklear is widely adopted in both professional and hobbyist projects for quick GUI development.