Categorize Email: Detect disposable email domains with machine learning

Hi! I just wanted to add more context for this project. For one of our SaaS projects we constantly experienced "fake registrations" where small fraction of users repeatedly registered new account every time their free trial expired :( We thought to collect mandatory credit card information during registration which would probably decrease such trend but this would also turn off our legitimate users who just want to try if our service fits their needs. So we decided for alternative approach... Based on "input from our bad users" we created internal tool which automatically categorizes user emails and rejects disposable / throwaway email providers or suspicious email domains. Based on multiple input signals our machine learning algorithm can categorize email domains which were previously not seen. This tool helped us resolve our issue. Since this problem is not unique to us, we decided to publish our tool publicly via simple REST API where every user can generate 100 monthly requests for free (should be more than enough for startups & small companies). Similar APIs already exist but most of them are too expensive to use or just too simple (databases where new domains are periodically added). Let us know what you think. Kind regards, Mia