English words by CEFR level - open source

You can try the following free open source resources:

• https://www.coe.int/en/web/common-european-framework-reference-languages/reference-level-descriptions
• For levels from A1 to B2 there are some textbooks for English vocabulary on the Books4Languages website that you can access and receive a Creative Commons license (for example, here is the link for the A1 level https://open.books4languages.com/english-a1-vocabulary/ ).
• For levels C1 and C2 there are two papers provided by the University of Macedonia and that you can access and download for free from here: https://www.toe.gr/pluginfile.php?file=%2F2143%2Fmod_resource%2Fcontent%2F1%2FLevel%20C1%20Word%20List.pdf for C1 and https://www.toe.gr/pluginfile.php?file=%2F2144%2Fmod_resource%2Fcontent%2F1%2FLevel%20C2%20Word%20List.pdf for C2.

This link appears to have a few lists of words based on level. It's not sortable like the EVR, but the content is still there.

I'd recommend putting the words into something like Anki. Anki has open source flashcard sets, so anyone can use the flashcards that other people upload to it, and they allow you to flip through flashcards giving each a rate of confidence that will determine how often the word shows up again. It looks like they don't have a dataset for English CEFR vocabulary by level, but I have seen some lower level CEFR vocab sets on quizlet

It also looks like although the vocabulary lists are licensed, you can use a text analysis tool from the same website for free to test your writing skills after you've gotten more of the vocabulary down.