Scheduled sending

Pass a future timestamp with any send and Sendibl holds the email until then — reminders, digests, and time-zone-targeted sends without your own job queue.

Schedule a send

Add scheduled_at (ISO 8601; a timezone offset is respected, otherwise UTC) to a normal send request:

POST /emails
{
  "from": "Acme <hello@acme.com>",
  "to": ["ada@example.com"],
  "subject": "Your trial ends tomorrow",
  "html": "<p>Heads up!</p>",
  "scheduled_at": "2026-08-01T16:00:00Z"
}

The email is created with status scheduled and goes out within a minute of its time. A scheduled_at in the past sends immediately.

Reschedule or cancel

PATCH /emails/:id          {"scheduled_at": "2026-08-02T09:00:00Z"}
POST  /emails/:id/cancel

Both work only while the email is still scheduled— once sending starts it can't be recalled. Canceled emails keep their record and get a canceled event.

Scheduled emails count against the monthly quota of the period in which they were created, and domain verification is checked at creation time — so a domain that loses verification before the send time will still block at handoff.

Next: Idempotency →