Google Classroom has become one of the darlings of the teaching world that has come out of this crisis. Its shallow learning curve and attractive UI made it an obvious choice for most educators. Oh, and I am sure the fact that it is free helped too.
One of the limitations is that you cannot simply upload grades from, say Google Sheets or another assessment tool. Well…not directly in the Google Classroom platform, yet.
This tutorial runs through the basics of uploading grades from Google Sheets into Google Classroom using Google Apps Script with the Classroom API.
Source: Google Apps Script: Upload grades into a Google Classroom Coursework Assignment – Yagisanatode