What is the best free software for sending bulk cold emails?

What is the best free software for sending bulk cold emails (mainly meeting requests) without getting blacklisted?

There is no reliable free software for sending bulk cold emails without the risk of being blacklisted. However, some suggested options include Mailchimp (although it is only free for up to 60% of its features), Sendy, SendGrid, and Amazon SES. Amazon SES allows you to send a large number of emails per day at a low cost, but it is not free. It is important to note that there is a fine line between a cold email and spam, and sending unsolicited emails can lead to complaints and trouble. To avoid being blacklisted, it is essential to have a quality email list and content that adheres to the proper guidelines.