smtp

Email with attachment

Content-Type: multipart/mixed; boundary="${separator}"; charset="utf8"
From: first.last@sub.domain.tld
To: first.last@sub.domain.tld
Subject: Email subject
--${separator}
Content-Type: text/plain; charset="utf8"

Email body
--${separator}
Content-Disposition: attachment; filename="file name"
Content-Transfer-Encoding: base64
Content-Type: application/octet-stream

${base64}
--${separator}--