As an avid Japanese learner, I always wanted there to be a simple online trainer for learning kana, kanji and vocabulary by JLPT level for Japanese learners.
So, I started working on a brand new, completely free and fully open-source app in recent months. It’s very new and still in its infant stages (and I'm looking to extend it to other languages too once it gets polished enough), but here are the features so far:

• Full JLPT vocabulary and kanji coverage, with more than 1000+ levels for you to play
• More than 25+ different fonts and font styles
• More than 100+ different color themes, with the ability to add and upload your own custom backgrounds
• 100% free and open-source, forever
• All learning materials 100% AI-free, sourced from reputable sources and available for full download and inspection

If that sounds interesting to you, you’re welcome to try it out and provide some feedback:
https://kanadojo.com/

GitHub just in case: https://github.com/lingdojo/kana-dojo

ありがとうございます!

This looks great, bookmarked to check it out later. Full Kanji coverage is awesome, I half expected there to only be Hiragana and Katakana. Kanji is what I still need to learn.

1000+ forks??
Looks slick but a little too much AI development going on here for me to want to use.
I currently use Renshuu and while its a little clunky I think it does everything this does and more, albiet in a less streamlined way.