Best way to run a python program from user input via a website

So I'm trying to make a website that allows users to write and execute python programs via a text area in the browser. My front end code is written in react and I was thinking about setting up a server to basically save the input as a file and use the exec function to execute it. After doing a lot of reading I now realize how unsafe this is. Is there a standard way of doing this? I'm very flexible as to how it's implemented. Thanks!