Wanikani equivalent for learning English vocabulary?

I'm wondering if there is an app/website for learning English vocabulary that works similarly to Wanikani. My adult students are currently using Quizlet, but it's not ideal. Specifically, I'm looking for something that:

1. reminds/urges them to review a certain number of words each day

2. comes with a "built-in" vocabulary list

3. ideally forces them to type in answers instead of just selecting them from multiple choices

(These students tend to be somewhat technologically challenged, so Anki is out of the question.)

Thanks in advance for any suggestions.