bcc | array | Yes | Blind carbon copy recipients (optional). |
body | string | Yes | The plain text body of the email. |
cc | array | Yes | Carbon copy recipients (optional). |
replyingToId | string | Yes | The ID of a message to reply to (optional). When set, the email is sent as a reply within the same thread. |
subject | string | Yes | The subject line of the email. |
to | array | Yes | The primary recipients (To field). |
