We don't recommend that you use such email sending platforms, because these are NOT cold email platforms. In fact, these below platforms DO NOT want you to send cold email through them. You need to have opt in emails for using with them.
- HubSpot
- MailChimp
- ConstantContact
- Vertical Response
If you use any of these platforms for cold emailing, your account in them may be suspended, because they are not setup for cold email. You should look for "Cold email tools" which are optimized and designed for sending out cold email.
Some of these cold emailing tools we have tried out in the past have been:
- Wavo.co
- Woodpecker.co
- Klenty
- SmartReach.io