My school made an interface a while ago for the students to be able to look at their grades. Sadly, this one have quite basic design and ergonomics. The main problem is that it doesn't show the global average.
I developed a small website in PHP with the Slim 3 framework. The interface is made with the CSS framework Bootstrap.
The website retrieves the grade directly from the school's website: the student logs in on the Calcul-O-Notes with its students credentials, these are then used to automatically connect to the school's server. The website then calculates and prints out the global average, the bonuses and adds colors to have a better idea of the student's grades compared to the others.