OpenSend docs
Schedule Email
Scheduled email lets application code queue a message for future delivery with the scheduledat field. The dashboard shows the accepted email record immediately; the worker sends it when the scheduled time is reached.
Supported scheduling window
OpenSend accepts future ISO 8601 timestamps with timezone information and the supported small natural-language form such as in 1 min, in 2 hours, or in 3 days. Values must be in the future and within the configured scheduling policy window.
Canceling
Use the email cancel endpoint or SDK cancel helper before the worker sends the message. After the worker starts delivery, canceling is no longer guaranteed.
Self-hosted caveat
Scheduled delivery requires the scheduled worker/cron path to run. If scheduled messages remain queued after their due time, verify the worker, queue, and cron authentication configuration.