Ryou Flashcards is a web app for learning and studying kanji and vocabulary words. The app contains more than 2,000 kanji and 8,000 vocabulary words, which you can study based on the JLPT level or the Japanese grade school level they appear in. You can also build your own study list using the "add to reviews" feature. The app features a spaced repetition system (SRS) and uses both multiple choice and written response format questions to help you review kanji meanings and readings.
As you work through a study list, the app keeps track of how many questions you've gotten right and displays your percentage of correct answers at the top of the screen. It doesn't seem to indicate how much progress you've made through a list, nor does it seem to keep track of which items you've gotten right or wrong. Ryou Flashcards seems like a very useful way to review for the JLPT or practice kanji that you've already learned, but it doesn't offer much in terms of learning kanji newly for the first time. Still, with its clean and simple design, it is a nice addition to your learning arsenal.