Wanikani for me is invaluable for learning kanji, it’s well worth as it slowly builds you up to more and more complicated kanji. Don’t undervalue their mnemonics either.
If you you have your own memorization techniques or like building your own mnemonics then
kamesame-a-fast-feature-rich-japanese-memorization-webapp
It works similar to wanikani and is free, has reviews (like wanikani) and space repetition, etc. Big plus is the general jpl lists they have defined and the ability to lookup and add words you come across to your study.
I have just started and it seems like a good mix, both wanikani and kamesame.
I am going for the lifetime subscription as others have mentioned here too.