How to collect in a list all the words from an article / book / site with their further study?

Question

English learning tools

Somewhere I met a description of a service (or a future service, I don’t remember), which collects words from the site and gives them out in a list, with the ability to sort by frequency.
That is, for example, I threw a link api.jquery.com and got a list of all the words, which you then work with.
Is there something similar?
PS This question is interesting in the context of studying English. language, it does not apply to seo.

Answer 1

I answer myself after a year and a half.
There is a good service for improving vocabulary: https://www.vocabulary.com
One of the useful features is the breakdown of any downloaded text into word lists and their further study.
Need to read an article? You throw it into a form, break it down into words, remove unnecessary ones, learn, then read an article with an already established vocabulary on the topic.

Answer 2

there are up to F and more
one of the popular
www.yazzle.ru
www.semonitor.ru
even with smart words like BM25 gee gee