Consider when creating an account through an API, they are sending an email confirmation message to access the generated URL and set their password.

There is no means / method of verifying such accounts through the API itself, what is a good approach to managing this setup?

I need to create many accounts, 50-60+ over the life time of the test suite run, how can I easily validate these accounts so they are usable?

-> waiting for gmail messages using the gmail API is much too slow and a very questionable approach.
-> drop the emails in some sort of drop folder?

I would prefer a non paid service solution if possible.