One of the worst platforms.
The claimed free version forces you nearly in all new AI and machine learning courses to buy pro subscription, in order to be able to finish it and get the certificate.
Additionally, in many courses, they omit data or knowledge required to know the answers apart from those who bought the pro version, so free users lose hearts and are forced to stop or buy pro.
My advise:
Check other apps!
Better alternatives out there. Great idea, slightly clumsy execution. You don't learn programming syntax the way you learn linguistic grammar. It doesn't require the same repetition and pattern forming, but rather conjunction with other variables, operators, rules etc.
The app became way too Duolingo-fied. Sololearn used to be an app to learn how to code and use different coding languages in a fun way, now it's just a game with coding elements (just like Duolingo won't help you learn a longuage in an efficient way), you can't learn anything with their new courses, it's kind of braindead (you don't even need to read anything to get a good answer!) (which is weird because of the code coach at the end of the lessons that have been unlocked from premium), you might learn something with their older courses (but be careful, they will be changed at some point)
I do not recomment this app anymore.
