ssmtp

To add SendGrid as an SMTP relay for ssmtp, edit /etc/ssmtp/ssmtp.conf and add the following:

1
mailhub=smtp.sendgrid.net:587
2
AuthUser=apikey
3
AuthPass=sendgridapikey
4
UseSTARTTLS=YES

Your changes will come into effect as soon as the next message is sent via ssmtp.