The datetime that the trip should depart (or arrive, for requests where arriveBy is on).
An
ISO 8601 string (
YYYY-MM-DDTHH:MM:SSZ,
YYYY-MM-DDTHH:MM:SS.mmmZ)
or a timestamp in milliseconds (ms since epoch, `1767225600000` = `2026-01-01T00:00:00.000Z`).
Use either datetime or the combination of date & time.
If datetime is present it will take precedence over date+time.
Optional. If not provided the journey is assume to depart "now".
Example:
2025-12-31T23:59:59.999Z.