How to use this

• With Chrome browser, open the extension menu or just navigate to chrome://extensions/
• Drag the netflix_ratings_exporter.user.js file into it
• Now navigate to https://www.netflix.com/MoviesYouveSeen
• Scroll to the bottom (it may take some time if you have a large collection of ratings), and you will see a button with the text Export
• Press that button and you will get a .json file with all your ratings

Roadmap

In the future you will be able to import the exported .json