Set scheduled_at to create an email now and release it for delivery at a future time.
Schedule a message
For a new send, scheduled_at accepts an ISO 8601 timestamp or a relative value such as in 5 min:
Relative scheduling is also supported:
Supported relative units include seconds, minutes, hours, and days. For deterministic production workflows, prefer an explicit UTC ISO 8601 timestamp.
Reschedule an email
Use PATCH /emails/{message_id} while the email is still a pending scheduled message. Rescheduling requires an ISO 8601 timestamp.
A successful update returns the message ID:
Cancel a scheduled email
Only pending scheduled emails can be rescheduled or canceled. Once a message has started processing, the mutation is rejected with a conflict response.
Scheduling rules
scheduled_at must resolve to a time in the future.- New send requests may use an ISO 8601 timestamp or supported relative value.
- Rescheduling requires a future ISO 8601 timestamp.
- Only pending scheduled emails can be changed or canceled.
- Use a distinct
Idempotency-Key for each distinct scheduling mutation.
Do not wait until the intended delivery time to reschedule or cancel a message. Queue processing can begin as soon as the scheduled time is reached.
