I'm using SendGrid as a main transactional mail service. By the moment it doesn't have Drupal 8 module, so I've made a basic integration with SendGrid API.
Module mostly based on Drupal 8 version of Mandrill integration module because I found it quite good and it has similar structure. Some functionality was removed, some added and rewritten for SendGrid API.
At the moment module have quite basic functions:
- Send emails with attachments.
- Support custom tags as 'metadata' array.
- SendGrid mail template select.
- Queue. All messages could be added to queue and send later on cron worker. Or you can also specify mail tags to send with queue and other mails will be send immedeately.
Installation instructions and code you could find on project page: https://github.com/Nikeev/drupal_sendgrid