Joomla
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 - "apikey"
 SMTP User must be the exact string, "apikey"
- SMTP Pass - <Your API Key>
 SMTP Pass is your actual API key