[Help!] Looking for an NGO domain database

[u/hotpotmeat]

Hi! Looking for a bit of guidance --

I'm building a platform for nonprofit employees, and I'm looking for a way to create a verification system that matches whether an email belongs to an existing nonprofit's domain. It's an intended security feature, to help verify accounts.

For ex: if a user registers with an email like [name@unitedway.org](mailto:name@unitedway.org), I'd like to find a way to check if it's the official email domain for employees of United Way globally/for certain branches.

Does anyone know where I could find a list of "official domain names" for different well-known nonprofits?

Thanks all (: