I have tried a few. Duolingo seemed to be good for making it fun to get interest but a lot of it was semi-random vocabulary. Try the Mango app for more practical conversation practice. It has flash cards that remind me of Anki that are nice for reinforcing memorization. It is free but I think has a premium option now.

Also, Tandem for practicing conversation with real people that speak the language via text, voice message, call, or video call.