The industry definition of a MERN Stack Developer is an engineer who can work on different levels of an application stack. The term stack refers to the combination of components and tools that make up the application. The components could be in the front-end or the back-end of the system.
The main objective of full stack engineer is to keep every part of the system running smoothly. A MERN Stack Developer can performs tasks ranging from resizing an image or text in a webpage to patching the kernel.