How to search profiles in social networks by email address automatically?

Question

Facebook

When receiving a letter, Yandex.Mail makes it possible to view the profiles of this user in social networks - take.ms/oKYHs
Profiles are searched for by email address.
Tell me, please, can a mere mortal startup organize such functionality? And how is it done?

Answer 1

api.fullcontact.com
I can be a bit wrong with the address .. search for help
looks for itself + gives api for such creativity

Answer 2

Networks have a "search for friends" function by accessing the contacts of the box. Theoretically, this can be automated.