Send or schedule an email

Send a single transactional email — now, or at a future time by passing scheduled_at. Provide the content inline as html/text, or reference a saved template with template (create one with Create a template). Pass an Idempotency-Key header to make retries safe: the same key replays the original result instead of sending twice. The response returns the new email's id — read its delivery status back with Retrieve an email, change a scheduled send with Cancel or reschedule an email, or send many at once with Send a batch of emails. A template in the marketing category sends to one recipient (no cc/bcc) and adds them to your contacts if they aren't one yet, because the unsubscribe link belongs to a contact: the new contact counts toward a Free plan's contact limit (at the limit the send is refused) and fires contact.created with source: "send". Requires the emails:send capability.