Too-Much-Java is an online code-grading platform that I built when I was a Teaching Assistant for an AP Computer Science A class.
In short, it allows instructors to create assignments, categorized by units and courses, and provide instructions as well as starter files. The student, on the other hand, can submit code files receive instantaneous feedback from TMJ.
The frontend is written in Vue.js and the backend in Django. Currently, TMJ only natively supports Java. However, feel free to edit the Django grading method to enable support for more languages.