CoCalc

The goal of the CoCalc project is to collaboratively calculate in the cloud using Python, SageMath, R, Julia, ... CoCalc let you run SageMath worksheets and Jupyter Notebooks online. It offers an online storage of projects consisting of worksheets, LaTeX documents, data files, Linux terminal sessions and much more. All document files synchronize their content between all collaborators in real-time. The terminal session allow you to run arbitrary programs. This encompasses tasks like authoring LaTeX documents, developing programs, have your own Git repository, connect to databases, etc.

Screenshots from Chrome Web Store