To create a scheduled push, simply add an additional parameter to the end of your payload:
&deliver_at=YYYY-MM-DDTHH:MM:SSZ
This parameter accepts configurations in the ISO_8601 date/time format. Click here for more information on ISO_8601 formatting.
YYYY = Year | MM = Month | DD = Day | HH = Hour | MM = Minutes | SS = Seconds
T is the time designator that precedes the time components of the representation. T is basically a placeholder and doesn't need to be changed or altered.
Z is the zone designator and follows the time components of the representation. Z represents the UTC / GMT time zone. A conversion chart for all the time zones can be found here.
The following message will send the push notification "Happy New Year!" to all registered devices on December 31st, 2016 at 11:59:59 UTC -- in other words, one second before the new year:
curl 'https://api.pushio.com/api/v1/notify_app/[APP_ID]/[SENDER_SECRET]' -d 'payload={"message":"Happy New Year!","payload_apns":{"sound":"default.wav"}}&audience=broadcast&deliver_at=2016-12-31T23:59:59Z'
NOTE: Once a scheduled push notification has been sent, it is currently not possible to prevent that notification from reaching the user.