Gmail - how to see new senders?

Question

gmail

Gmail receives a large number of letters from customers. Is there any way to mark letters from clients who have written for the first time (this person has never written before)? It is through the web interface of Gmail.
ADDITION. Since there are no answers, I will formulate the problem in a different way - you need to count new customers, broken down by days/weeks/months. How can this be done? Perhaps one of the email clients has the appropriate plugins?

Answer 1

0) https://www.streak.com/ (Maybe)
1) IMAP
2) API (Maybe)