Hi! I have over 6 years of working experience in .Net, Asp.Net, C#, VB, SQL Server, SharePoint, Windows Communication Foundation, Rest API, Web API, JavaScript and its libraries, HTML, Bootstrap, and also some third party tools. Well versatile in windows, desktop and web applications. I went through your requirement and I am confident in delivering a well documented project with all the required functionalities.
There will be two steps involved to verify if the email address exists.
1) First check if the domain exists by sending and receiving a socket response.
2) Then, after checking domain exist, we can do handshake with the Mail server and see if the email exist or not.
If you have any questions / queries at your end then please inbox me so that I can explain you in details and we can move forward with the project.
Thanks & Regards.