Duolingo

Duolingo is one of the most downloaded free language apps out there. The game-like format of the daily 5-minute session makes learning Japanese accessible to people of all ages and skill levels. It's a terrific way to get a head start on expanding your vocabulary, and you can easily tailor your studies to fit your needs. When you're ready to devote more time, you can easily adjust your study schedule to accommodate your needs. This is a family-friendly app.

Website: https://www.duolingo.com/course/ja/en/Learn-Japanese