Cold emailing isn't illegal. But every country has its own rules that you must follow while sending commercial emails. For example, if you are sending it to prospects from the US, you must ensure that it complies with the CAN-SPAM rules. Here are some tips to avoid getting blacklisted while cold emailing: - Reveal your identity in the email - Avoid clickbait subject lines - Send relevant emails to your prospects - Provide an opt-out link To know more about CAN-SPAM compliance