Spamkit-mailer Free Mass Mailer feature Asynchronous Delay in per email Letter preview Usage Create your smtp config file create txt file and put your smtp creds in this formate { yoursmtpurl:smtpport:smtpusername:smtppassword } Import all necessary stuff like smtpconfig.txt file, mail, letter, subject list, from list Choose how you want to send the emails Asynchronously { start async } { Fast } This option will create ten connection at the same time Normal { start } { Slow } Set Delay if You want add Delay in per email What next Fixing add manually button screenshot