Joomla supports sending email over SMTP. To have Joomla relay email through SendGrid go to Site > Global Configuration and change:

  • Mailer – SMTP
  • SMTP Host - smtp.sendgrid.net
  • SMTP Port – 587
  • SMTP Security – STARTTLS
  • SMTP Authentication - Yes
  • SMTP User - sendgrid_username
  • SMTP Pass - sendgrid_password