Holy moly. Sending unsolicited marketing emails is the very reason CAN-SPAM came about. The fines for violations would crush most early stage startups.
If you are going to continue further with email, please read up on CAN-SPAM, inboxing, SPAMHAUS, DKIM.
If you are going to continue further with email, please read up on CAN-SPAM, inboxing, SPAMHAUS, DKIM.