Any API or Opensource to build interactive coding exercise site like freecodecamp?

Hi we are looking forward to build an interactive coding exercise portal like freecodecamp or codecademy to run our internal courses. Are there any API’s to use or what is best option that we can consider instead of building from scratch?

PS: All the courses are related to web development

Thanks in advance

FCC is open source, so you can look at what tools they are using.