대량 메일 발송

https://www.google.com/search?q=email+%EB%8C%80%EB%9F%89+%EB%A9%94%EC%9D%BC+%EB%B0%9C%EC%86%A1&rlz=1C1CHBF_enUS754US754&oq=email+%EB%8C%80%EB%9F%89+%EB%A9%94%EC%9D%BC+%EB%B0%9C%EC%86%A1&aqs=chrome..69i57.5576j0j7&sourceid=chrome&ie=UTF-8

https://cloud.google.com/appengine/docs/standard/php/tools/using-local-server?hl=ko#using-sendmail

https://medium.com/sjk5766/aws-ses-smtp%EB%A5%BC-%ED%99%9C%EC%9A%A9%ED%95%9C-%EB%8C%80%EB%9F%89-%EB%A9%94%EC%9D%BC-%EC%A0%84%EC%86%A1-%EC%8B%9C%EC%8A%A4%ED%85%9C-%EC%A0%95%EB%A6%AC-e32863abbe4c

https://mailtop.net/cscenter/cscenter.php?DT=manual_view&id=251

https://www.tason.com/to/email

https://blog.readiz.com/135