If you ever need to send many emails at once, an email queue system will reduce the strain on your web server by sending emails a few minutes later in a separate process (usually). After some searching I found an easy to use one called post_office.
The configuration is very simple and emails get sent using a cronjob. It doesn’t require Celery/RabbitMQ or anything else. I won’t bother posting any configuration details because the GitHub page contains everything you could possibly want.