Sends a plain email from your own mailbox right away, through Gmail or Outlook. Use it for simple transactional email. It creates no Mixmax message: there is no tracking, no Live Feed entry and no CRM logging. For tracked email, use POST /v1/messages and then POST /v1/messages/{id}/send.

The email always comes from you, whatever from says. Send to as one address object; Gmail accounts also accept an array of them, but Outlook accounts need a single object and also need from.