A drop-in solution to send all SilverStripe emails through SendGrid
composer require unclecheese/silverstripe-sendgrid-mailer
The mailer will activate once the following environment variable is set:
SENDGRID_API_KEY='mykey'
If you want to test SendGrid from a dev environment, you can force all emails to a test address.
SENDGRID_TEST_EMAIL='myemail@example.com'