repl.it integrates this with their classrooms product to make it into a structured learning tool with assignments and automatic evaluation of solutions. Direct link to the course: https://repl.it/community/classrooms/17650
It's the same technology (backed by Expo) but it's integrated in Repl.it's platform and community. Additional benefits include the ability to teach and/or build online courses. Or if you're already using Repl.it it's cool to have all your programs/experiments/homeworks/prototyping in one place.
repl.it integrates this with their classrooms product to make it into a structured learning tool with assignments and automatic evaluation of solutions. Direct link to the course: https://repl.it/community/classrooms/17650