OpenGL.org --http://www.opengl.org
The Industry's Foundation for High Performance Graphics. An independent consortium, the OpenGL Architecture Review Board, guides the OpenGL specification. With broad industry support, OpenGL is the only truly open, vendor-neutral, multiplatform graphics standard
Vulkan API (Khronos) --https://www.khronos.org/vulkan/
Vulkan is a new generation graphics and compute API that provides high-efficiency, cross-platform access to modern GPUs used in a wide variety of devices from PCs and consoles to mobile phones and embedded platforms.