Kanji recognition tool is useful. Overall it has a lot of features to study vocabulary. It gives examples of the word you look up in a sentence. You can tap other words in the sentence to look them up, and retrace your steps back to the word you were looking up. Information about the word is very organized. All official conjugations are listed. Many compounds are listed, when applicable. Highlighting a word is possible.
If you can’t decide what word you want to look up, clickable words start scrolling across the search screen from right to left. I don’t use any other apps for Japanese other than Audible.