I wonder what languages programmed SoloLearn ???Any ideas...?😉😉

Answer 1

I believe it was the developers that programmed SoloLearn. 😉

Answer 2

Just a guess:

PHP + MySQL server-side, maybe some C/C++/Ruby for custom supporting programs, and possibly some scripts in Python.

HTML/CSS/JS for client side, obviously, but also some kind of Framework -- most likely jQuery -- and Font Awesome or an equivalent for icons.

Then the actual coding environments are likely small VM's run in their own little processes that only run long enough to execute the code and are then destroyed for security purposes. Alternatively they may be using Docker and just destroying/re-initializing the instances when they feel like it.